Marque of celebrity
CARS are signifiers, perhaps the quickest and most effective way of telling the wider world about yourself.
Even driving something modest is doing just that, particularly if everyone knows you could - if you wished - drive anything you please.
According to the new marketing tome The Consuming Instinct, by Gad Saad, a scientific study has shown that a man's testosterone level actually increases while driving a Porsche.
''Much of what we do as consumers is ultimately related to sex,'' Saad writes. That could explain a lot about what's out there mixing with the traffic.
Here are a few cars owned or driven by famous people, old and new, recent and late. Who are they signalling what to? We'll let you make that decision yourself.
John Lennon - Rolls-Royce
John Lennon didn't gain his driver's licence until 1965, when he was well into his 20s. Even after that, he didn't drive often. Nor did he drive well, it is said, suffering from dreadful short-sightedness and a general lack of interest.
Still, he bought a sky-blue Ferrari 330 GT just after passing his driver's test. He also owned Minis and the rather overstated three-tonne bespoke-bodied Roller on our cover. It was delivered in 1965, with black paint, and was probably the car that took the Beatles to Buckingham Palace to receive their MBEs.
Lennon soon added a radio telephone, unusual for the day. Even more unusual was his decision two years later to give the car a paint job to go with the summer of love and everything psychedelic and Sgt. Pepperian.
In Scotland in 1969, Lennon smashed a more prosaic Austin Maxi, mildly injuring himself, his son Julian, new wife Yoko Ono and her daughter, Kyoko. He had driven that particular car on his holidays because he ''wanted to be normal'', he told a friend.
He later had the Maxi - with stoved-in front end - put on a plinth in his garden at Ascot as a supposed reminder of mortality.
'P.Diddy' Combs - Bentley
Blinged-out Bentleys are the thing with many rappers, though Lamborghinis, Hummers, new gullwing Mercs and 1960s American convertibles (suitably modified and decorated) have also proved popular.
In their search for excess, some rappers have even bought Maybachs. No, really. Sean Combs (aka Puff, P. Diddy, Puff Daddy, et al) even bought one for his son - for his 16th birthday.
Combs's car obsession may have run out of control at times. According to a 2005 report, he put 150 of his pimped-up cars for sale on eBay to clear a bit of space in his garage.
The Puffster is pictured here with a Bentley Arnage. He's also been seen getting around recently in a Rolls-Royce Phantom saloon, a Phantom Drophead Coupe and a Lamborghini Gallardo convertible.
The Queen - Range Rover
When one drives at Balmoral, one tries to do so in a properly British vehicle. Though, it must be said, one finds this harder and harder to achieve nowadays.
My people tell me Range Rover is now owned by Tata. Messy business. Of course, if one was Empress of India like great-great-grandma Victoria, one's collection of these cars could still be claimed as Empire-built. I'm informed that Morgan and McLaren claim to make truly British cars.
But surely neither would be as good as my Range-Tata for hunting down peasants, sorry, pheasants.
Tom Cruise - Mustang
Tom Cruise, the American actor with vaguely Australian links, considers himself a ''car nut''. Some think that's one word too many.
He was seen driving around in this Mustang Saleen S281 circa 2003 (Saleen was an aftermarket seller of hotted-up Mustangs), though he has also driven and owned many Porsches.
As an actor, he took the wheel of a 928 in Risky Business and a 356 in Top Gun. He is said to own a 911 Turbo.
Cruise has also been photographed with a Bugatti Veyron that is said to be his property and various motorcycles (mainly Harleys).
The Mail on Sunday, one of those quality English tabloids, reported in 2008 that Cruise was using a bomb-proof car (brand unspecified) because he feared for his life from anti-Scientology groups. Next they'll be saying he's preternaturally short and jumps on couches.
Christina Aguilera - Ferrari California
The American triller has been seen getting out of the back of all manner of luxury cars, including a white Rolls-Royce Phantom, a white Range Rover and a white Chrysler 300C. Noticing a trend here?
When it comes to Ferraris, though, she's obviously sticking with the red, probably for the resale value.
This is the Ferrari California she reportedly bought with her former husband, Jordan Bratman (that's him at the wheel, though he appears to be wearing a false nose and moustache to avoid detection).
The Aguilera-Bratman duo paid what the press said was a ''whopping $US211,000'' for this car. They were obviously smart enough not to buy it in Australia.
Arnold Schwarzenegger - Hummer
In 2003, an Austrian bodybuilder-turned-blow-em-up film actor with no political experience became Governor of California and, therefore, in charge of one of the world's biggest economies.
Satirical newspapers, such as The Onion, reported the facts completely straight. There was nothing they could really add.
One of many complications - beyond understanding what the hell the Governator was saying beneath that accent - was that California was the US's greenest state in terms of motoring legislation.
Schwarzenegger, by contrast, was a long-time fan of the obscenely wasteful Hummer. He'd actually bought (or had been given) the very first civilian version in 1992, a three-tonne H1, and built up a collection from there.
During the gubernatorial campaign, Schwarzenegger pledged to convert one of his Hummers to run on hydrogen.
He's lately been seen in a Porsche 911 Turbo convertible, a Dodge Challenger and an Excalibur - a ghastly modern-ish homage to the 1920s Mercedes SSK.
Paris Hilton - Bentley
Paris Hilton, the pioneer of the now-popular uber-slut look, was seen at the helm of a Bentley Continental GT in 2005.
Three years later she famously (that's famous as in ''Paris Hilton-famous'', ie, of no consequence to anyone) ordered an all-pink example of the same car with ''PH'' lettering replacing the ''B'' in many of the badges.
She said her pink Bentley's heavily tinted glass was to deter paparazzi. Er, wouldn't a more sedate colour scheme have been more help … and, anyway, without paparazzi, what exactly is Paris Hilton?
Earlier this year, a friend of Hilton's smashed a Cadillac Escalade into the pink Bentley.
Larry David - Prius
For quite a while, the Toyota Prius petrol-electric hybrid has been a popular choice for celebs to be seen in, or with. Its softly-softly environmental reputation makes them feel warm and gooey as they make their way to their private jets and football-field-long yachts.
This is Larry David - of Seinfeld and Curb Your Enthusiasm fame - turning up in one Prius to present another one to the winner of a ''Curb Global Warming'' contest.
The Prius's role as chariot of the righteous has to some extent passed to the Tesla and Nissan Leaf and will no doubt soon be handed over to the BMW i cars, until the next thing comes along.
Clint Eastwood - Ferrari 365 GTB4 BB
Clint is a car man. He made Gran Torino, a film starring a 1972 Ford, for goodness sake. He'd put cars in his westerns if he could get away with it.
Away from the screen, Dirty Harry has made his day with a long list of interesting cars, including a 1958 XK Jag, bought new (or near new), a Ferrari 275 GTB and this 365 GTB4 BB.
He was rumoured to have bought a VL Group A Commodore when he visited Australia in the 1980s.
Bergman and Ferrari
There is something better than having a Ferrari: having a Ferrari created just for you. The beautiful Ingrid Bergman had just that honour in 1954.
The Swedish actress became a huge international star after appearing with Humphrey Bogart in Casablanca in 1942. A few years later, while making a film in Europe, she fell in love
with Italian film director Roberto Rossellini, an avowed Ferrari fan.
Bergman and Rossellini were each married to another at the time and the ensuing scandal looked set to destroy her Hollywood career (today, of course, it would be used as a promotional tool).
The compensation was that Rossellini bought Bergman a Ferrari 212 Inter coupe in 1953. The next year, Rossellini commissioned this bespoke Ferrari 375MM coupe for Bergman.
The beautiful bodywork was by Scaglietti, the coach-building company that Ferrari would eventually buy. A silvery-tan-grey external paint colour was also created just for this car and is now available in the Ferrari colour chart. Ask for it by name: Grigio Ingrid.