I've just hit the tipping point where I've been driving for longer than I've not - I'm 34 and started driving when I was 17. Have had a good few really "meh" cars in my time and am currently driving a '98 Mondeo (though it is a 2.5l V6). Though in keeping with most posts in this thread, I'll have to say that my other car is a 30-litre V20, quad-turbo Lamborgini F430 Quatroporte Supervoloce GTi (diesel) which has eleventy-million BHP and does 0-60 in -1.2seconds (it's so fast that it breaks the speed of light and stops obeying the laws of physics, meaning it is doing 60mph before it starts moving), which I've owned since I was 6. Though I can't get pictures of it right now, it's in the garage getting the seats re-upholstered with supermodel skin.
I've done a good few driving days and can say that no driving game (GT5 included) really replicates driving an actual car quickly, though I wonder if that's a "feeling" thing - there's not a proper sensation of speed, you can't feel what the wheels are doing, how much the car is rolling etc.
I was once driven around Silverstone by Tiff Needel in a GT-spec Ferrari (I know that will be setting off a few ******** alarms, but it's true). When he asked what I did for a living and I told him I worked in games, he said "oh year, I've had a go of that new PlayStation F1 game (which I was working on at the time). It's good, but you never get the true sense of what the car is doing". He then proceded to brake so late into a hairpin that I slightly wet myself. Slightly.