When BMW unveiled its 750hL earlier this year, the media response was muted. This despite the fact that the 750hL is the world's first production-ready hydrogen powered passenger car. Well, hydrogen and petrol, and, um, it's actually super-cooled hydrogen, but hey, we are talking about a luxury car that can steam from zero to sixty in 9.6 seconds and drive 300 kilometres between fill-ups, without a single harmful emission.

Sure, a few "challenges" remain before the 750hL will replace the semi-electric Toyota Prius as the tree hugger's favourite. At the moment, only two specialist filling stations offer super-cooled hydrogen (LA and Munich). There are "safety issues" surrounding the use of a fuel that can freeze your fingers right off. Even so, BMW's self-confessed "transitional vehicle" marks the global automotive industry's path towards a hydrogen-powered future.

GM, Ford, Daimler-Chrysler Volkswagen, Nissan and Toyota are all committed to selling zero emissions, hydrogen-powered cars by 2010. Which raises an interesting question. Why? Considering the gigantic cost and Herculean hassle of creating an entirely new means of propulsion, you'd think car manufacturers would prefer to clean up the existing petrol engine and call it good. And so they would. If they could. But they can't. Blame– or thank– California.

In the 1970's, California forced car manufacturers to lower emissions. Regulators established a precedent (foreshadowed by Ralph Nader): politics dictating automotive development. In other words, the free market was cut out of the action. Now that the world has decided that Global Warming exists and SOMETHING MUST BE DONE, something will.

Hydrogen is the left leaning environmentalist's fuel of choice. The power to convert water into hydrogen and oxygen gas can come from anywhere: solar, wind, thermal, tidal, nuclear, even rotting garbage. Replacing the western world's 100 million plus petrol-driven cars with hydrogen-powered vehicles could trigger the long-awaited, politically correct development of renewable energy sources.

More important to those on the other side of the political spectrum, such a diverse hydrogen infrastructure would free the western world from the financial, military and political cost of drilling, refining and distributing Middle Eastern petrochemicals.

September 11th gave both sides in the pro-hydrogen camp new impetus. America and its allies finally woke up to the possibility– the necessity– of reducing its dependence on foreign oil. Hydrogen power suddenly became a national priority.

If only. While recent events have liberated new funds for hydrogen research, war is still the more practical option. Manufacturers have several hurdles before they can even think about filling the new world's hydrogen order. First, they need to perfect the hydrogen fuel cell.

Size matters. The most efficient fuel cells are two to three times larger than a conventional petrol engine. That's fine for a bus, but not a car. Case in point: Ford's Focus FCV (Fuel Cell Vehicle). Engineers had to raise the floor and eliminate the boot to fit a 22-gallon hydrogen tank. The resulting FCV weighs 1200lbs. more than it gasoline-powered equivalent, travels just 100 miles between fill-ups, and it's not even on the same performance planet as the Focus RS.

Car manufacturers and lawmakers alike are throwing billions of pounds at universities and R&D departments in the search for a smaller, more powerful hydrogen fuel cell. So far, so bad.

Meanwhile, GM estimates that a suitable fuel cell would be two to three times as expensive as a gasoline engine. Industry cheerleaders claim that costs will decrease as the market expands, like they did for mobile phones and PC's. Manufacturing techniques would have to evolve quickly, and the Marketing Men would have to convince millions of people their hydrogen car will not Hindenburg.

There's only one way to accelerate the process: raise the price of gasoline to levels that would give "Red" Ken Livingstone wet dreams. Political suicide. Anyway, even if a practical, cost-effective hydrogen technology existed, who's going to pay for all those new filling stations?

The smart money is on the oil companies. BP, Shell, Texaco and Exxon. All the big oil companies are looking to build hydrogen production plants next to their oil refineries. The power to transform water into hydrogen gas would come from… oil. To remove pollution from the process, carbon wastes would be removed at the well or refinery, and then buried underground. While Greenpeace and chums aren't buying "carbon sequestration", it's not a debate destined to mobilise the masses.

The idea of using Middle Eastern oil to make hydrogen to fuel zero emissions passenger cars is bizarre, to say the least. But like the BMW 750hL itself, it's the unavoidable short-term bridge between the current set-up, and the one to come. Given the political climate, resistance to the concept is unlikely. In fact, providing BMW removes the iDrive and brings down the zero to sixty times, even petrolheads may be ready to face a hydrogen-powered future.

For those of you on the English side of the pond, a "Hummer" is a large, wide, low-slung 4X4 built in the US of A. The off-roader first invaded American consciousness during the feature-length TV series known as The Gulf War. An Austrian immigrant (who parlayed his ability to lift heavy weights into something not unlike an acting career) led the civilian rush to transfer the H1 to the suburban theatre. GM's marketing radar detected the trend and annexed Hummer. This year, the General finally spat out a "civilian" Hummer: the H2.

Mechanically, the H2 is fundamentally similar to the military-spec H1. Both vehicles have astounding off-road capabilities. Both vehicles have been beaten with an ugly stick. Repeatedly. But what sets Hummer apart from all other American SUVs—aide from the fact that the Hummer was originally designed to help kill people—is the way GM has set out to sell the beast.

GM calls it "retail-tainment". Obviously, any concept with a name that assaults rather than trips over the tongue is asking for trouble. As Elvis said, if you're looking for trouble, you've come to the right place. Specifically, you've come to Milwaukee, Wisconsin, home of the world's first Hummer dealership. It's ground zero for GM's campaign to make car dealerships less of a battleground, and more of a theme park. Or, in this case, a battleground theme park.

Confused? Think of it this way: car dealerships haven't changed in the last 100 years. In the main, they're huge glass structures with sparkling cars and wilting ferns, populated by packs of skulking salesmen. More than thirty years after the mall-ing of America, the car industry has finally twigged that even Nazi architect Albert Speer couldn't have designed a more sterile, intimidating environment than the traditional automotive "fish bowl". The six million dollar Hummer dealership is the inevitable result.

John Horgstrom's Hummer dealership is the General's first ground-up attempt to create a user-friendly retail environment. In this case, the "fun" is "themed" on the brand's military heritage. The building was built to look like a gigantic Quonset hut, the corrugated iron shed used by the American military during WWII. You enter Hummer HQ through a gigantic letter H. Although there's no armed guard at the door to salute you, the dealer's civilian staff have a goal: to get customers into a Hummer and onto the adjoining obstacle course.

The course is where the going gets tough, and the tough buy an SUV. It demonstrates the Hummer's abilities in conditions the average SUV driver would never see outside of a TV commercial (or a Hummer dealership). It lets salesmen use their off-road driving skills to establish dominance over their customers. And it suffuses a buyer's bloodstream with sales-friendly endorphins.

The course is, in fact, the future. Providing the Milwaukee experiment goes to plan, providing GM commits to a third model line, the General will deploy 156 themed Hummer dealerships across the Land of the Free. Industry savvy pistonheads will recognize the trend. Land Rover has already experimented with on-site off-roading. Given the macho emotional investment needed to buy something so obviously inappropriate as a road-going off-roader, the "theme-ing" of the 4X4 business is bound to succeed, and continue.

"Retail-tainment" will eventually extend to other automotive genres. How long before Porsche dealerships look like pit lane garages? How long before Aston Martin dealerships become gentleman's clubs? How long before Renault dealerships morph with patisseries, offering a choice of fresh-baked croissants or half-baked Avantines? Not long. And not before time.

The move towards "retail-tainment" will generate significant benefits for both consumers and carmakers. For one thing, it will keep manufacturers focused. Hummer's huge investment in military chic will force it to stay within its suburban warrior remit. Porsche will have to choose whether it wants to sell road-going sports cars or Paris Dakar wannabees. Ford, Mercedes, BMW, Toyota and the rest will all have to figure out what they do differently than the other guy, then create an appropriate retail environment to "sell the sizzle".

Will Ford go for value for money, and create a giant automotive Tesco's? Will Mercedes create a dealership that looks like Dr. No's lair, perfect for plotting world domination? Whatever retail theme a car maker chooses for his products, the huge investment required will make it harder for them to change "brand identity". As a result, we can expect to see the birth of more specialised sub-brands (e.g. Toyota's Lexus), and more finely honed products.

As silly as it sounds, automotive "retail-tainment" represents a long overdue revolution. Old-style car dealerships are one of the most unremittingly inhospitable sales environments ever devised. It's no surprise that most people would rather go to the dentist than face the sharks cruising the fish bowl. No matter what the ultimate impact on the auto industry, anything that makes buying a car more fun than root canal surgery has got to be a good thing.

Would you buy a Land Rover sports car? What about a Porsche off-roader? Now think carefully. Sure, the Porsche Cayenne will be the worlds fastest and best handling 4X4. So what? The Sultans of Stuttgart will have answered a question no one asked: how do I get a truck to lap the Nurburgring faster than a Nissan Skyline GT-R? Here in the real world, the biggest question vexing MPV drivers is this: what time does Janie's football practice end? Considering the cataclysmic damage these lumbering behemoths inflict on lesser vehicles at a walking pace, the average MPV driver needs less speed, not more. Put Mum in a Porsche off-roader and it's only a matter of time before the entire soccer team is goading her to blow off the jerk in the Merc.

Safety aside (as always), the Cayenne will sell. Plenty of posh Porsche posers will love seeing their Cayenne and Carrera snuggling together in a darkened garage. I find the concept incestuous and redundant. Stick snow tires on a Carrera 4 and you've got a four-passenger car that makes normal sedans seem like Ice Capades rejects. The Cayenne adds elevation to the equation, but it also introduces mass. Drivers will be able to see into next week, but they'll constantly be out-handled by smaller, lighter machines. Still, as a capitalist cheerleader who once owned a TVR, I can hardly begrudge buyers a car they need like they need satellite-controlled headlights that swivel to follow the road. I'm more concerned about the Cayenne's effect on Porsche.

The Cayenne is a sign that Porsche is making too much money: £5385 per car. This phenomenal, seemingly unstoppable success has given Porsche Hitlerian hubris. OK, we've done Europe. Let's invade Russia! OK, we've done sports cars. Let's take on GM, Ford, Chrysler, Land Rover, Mercedes, BMW, Toyota and Mitsubishi! The fact that Porsche can't make enough Boxsters and Carreras to satisfy demand seems to have escaped the notice of their Bored of Directors. Lest they forget, the upcoming, V10-powered GT will put the company toe-to-toe with Ferrari's F60. With the Cayenne, Porsche doesn't blink so much as sneeze. Is this really the same company that agonised for years about making a four-door 928? It's as if they decided to apply their motor sport heritage to designing brief cases. Oh wait, they have.

The process of applying brand values to increasingly disparate products is called brand extension. Like hair extensions, you think you're getting something better. You're not. Mercedes, once proud producer of bank vaults on wheels, slaps its star on downmarket tat. The next thing you know they're making cars so nasty they're called Chryslers. And BMW's product range may lead the casual observer to believe that a carmaker can do it all, but I doubt they've ever tried to corner a Z3 on a greasy roundabout. Mercedes, BMW and Porsche will all learn that extending a brand damages your roots. Sooner or later, they'll all have the economic equivalent of a bad hair day.

A successful carmaker must have Focus. Just ask Ford. All their cars are sold on value for money. Maintaining this single-mindedness imposes natural limits on a brand's potential. Ford will never beat Bentley; value for money is not exactly the luxury car buyer's first concern. Similarly, you'll never see a fifty-acre field filled with pre-registered Bentleys. So what's the point of the Cayenne? It may add a zero Porsche's balance in the short term, but it's an evolutionary dead end. In the 4X4 market, Land Rover owns the high ground, where people still care whether a car can climb a tree (or at least looks as if it can). Ford and Chrysler own the low-road, where middle-class Moms have better things to spend their money on than an off-roader than can hurtle her brood down a highway at 155 miles per hour. The Cayenne will be smack bang in the middle, scrabbling for purchase in a tiny niche, forever fighting off Mercedes' ML and BMW X5.

Meanwhile, carmakers that focus all their efforts on creating machines that go like Hell will continue to thrive. As long as Peter Wheeler shovels massive grunt into lightweight bodies, there will be a TVR hovering around at the bottom of the J D Power survey. As long as Lotus makes cars that corner like roller coasters, TVR will have suitable company on that list. There will always be a hard core of wealthy enthusiasts who believe that driving "off-road" means one thing: they've lost control of their sports car. Every man-hour Porsche spends on the Cayenne—designing, marketing, servicing, etc.— is one man-hour less for maintaining and extending their dominance in the sports car market. In other words, the Cayenne is a waste of time.

At the end of the fiscal year, the best thing a world-class sports car maker like Porsche can make is… wait for it… sports cars! Porsche ignores common sense at its peril. Which reminds me; didn't Lamborghini once build a four-wheel drive thingy? Oh yes, now I remember: the LM02. It was an awesome beast, powered by a 420bhp V12. That was 1986, just before Lamborghini lost their independence. Again.

The new Range Rover is Top Gear's magazine's Car of the Year. Car? I'm sorry, but my definition of a 'car' doesn't include vehicles taller than six feet that weigh nearly two and a half tons. The Range Rover is, according to US environmental and safety regulations, a truck. Truck by name, truck by nature. No amount of ABS, traction control and terrain sensing suspension can alter The Laws of Physics: mountainous mass X V8 acceleration + slippery surface = endless understeer oblivion. As Top Gear's own writer put it, the Range Rover's quest for soft-road world domination will ultimately end 'in a ditch'.

Don't get me wrong; I'm sure the new Range Rover is a damn fine truck. Isn't it? I've yet to pilot the beast, but the few British journos who weren't busy singing 'Land Rover of Hope and Glory' at the truck's launch noticed a few 'glitches'. One version's adjustable air suspension got stuck in mid-air- a problem not unknown to owners of the previous model. One or two reviewers also didn't fail to notice the Ranger's prodigious thirst (12mpg), sloth (0 – 62 in 9.2 seconds) and square-rigged susceptibility to side winds. But hey, what do you expect? It's a truck. A truck that still hasn't released its Euro NCAP crash worthiness rating.

Aside from semantics, build quality, global warming, performance, handling and safety, my biggest problem with Top Gear's selection is that I can't understand their criteria. The magazine avoided the thorny issue of how a Range Rover is superior to a Lamborghini Murcielago (aside from the obvious fact that you can say 'Range Rover' without sounding effeminate) by simply leaving out the bit that explains how they made their choice. Well, TG does say the Range Rover has more 'all round excellence' than the luggage aversive Lambo. OK guys, but what makes the Range Rover more of an all-rounder than a BMW Five Series? The fact that it can drive to places where the rescue service arrives in a Toyota Landcruiser? I don't think so.

It's probably more a case of wishful thinking. TG's post-Empire unconscious must instinctively yearn for an English car that's a world-beater, even if it is a truck. Someone should tell TG that even nostalgia ain't what it used to be. I once took out a small village in a barely controllable, formerly all-conquering Jaguar XK120 (which may have been the car's intention, but not mine). Anyway, like the Royal family oneself, the Range Rover is a murky collection of British and German genetics. Even overlooking its BMW engine, I wonder if TG would have given Ford's latest truck the gong if it had been built in Detroit. Like, say, the similarly inoffensive Cadillac Escalade. Again, methinks not.

TG's editors should take the time to define excellence before they publicly announce it. Otherwise, they open themselves up to charges of misguided patriotism-or worse. (I once saw a vicious pub fight that started over the relative handling merits of a Nova vs. a Saxo. A Black Maria won.) If excellence equals technological innovation, anoraks will remind you that the new Range Rover's monocoque construction and air suspension predate the Defender. If excellence means drop-dead style, only a Multipla owner could deny that Mercedes' new SL is a more elegant evolution of a familiar form. And if excellence means bang for the buck, Scooby Doo, Landie don't.

To be fair, TG did a lot better in the semis. They recognized the Civic Type-R as an engineering masterpiece that costs only slightly more than the VAT on a Ferrari 456. They admitted that the Subaru Impreza Turbo is still the best- if most insect-like- driver's car ever unleashed on English roads. The plastic fantastic Renault Avantine earned a justifiable nod as the boldest new mainstream, um, thing. And who can [be bothered to] argue with their choice of the Nissan Primera as the best 'medium car'? They're all sane, safe choices for Best in Class. Porsche owners may howl with high-octane indignation at TG's conclusion that an Audi TT is better than a 911, but it's hard to share their outrage. After all, they have a 911 with which to console themselves.

I wish TG's final choice had been a little less NHS, and a lot more Pop Idol. A 'chalk or cheese?' people's poll would have been a far more equitable way to select an overall winner from such disparate machines. Perhaps it's a bit much to ask for democracy from a magazine spawned by a TV program on a channel funded by a mandatory tax on people's TV sets. So let's do it ourselves, through that newfangled thing called the Internet! Simply press the comment button below and nominate your own Pistonheads Car of The Year. Don't forget to include your justification. I'll start by nominating the BMW M5. It's the best car in Britain because I bought one. So there.