Ok, first attempt...
1. 4x4 - The Best (tm) - a Range Rover Vogue (possibly breathed on by Overfinch)
2. 'People Carrier' - a full size Van Hool bodied Volvo coach kitted out to accommodate a dozen or so people in absolute decadent luxury. And for longer journeys, a similarly equipped Boeing 737.
3. Trackday car - great fun that a Redical would be, my ageing bones require some protection from the elements, so a Porsche 997 GT3 Cup.
4. Fancy occasion - Rolls Royce Phantom. Nothing else even comes close,
especially the Maybach - a hateful car for lottery winning chavs.
5. Small/city car - a London Taxi. If it's good enough for Stephen Fry, it's good enough for me. Go anywhere, stop anywhere, annoy everyone.
6. 4 door/4 people - a Bentley Arnage T. Not as decadent as the Phantom, but unparalleled for performance
and luxury.
7. Exotic - Porsche Carrera GT. I know, I've already got one Porsche, but the Carrera GT is the best of the supercars. Maybe not as awesome to look at (or quite as quick) as the Enzo, but most definitely a superior piece of engineering.
8. Open top/roadster - Pagani Zonda C12 Roadster. Possibly even more exclusive than my exotic choice, but hey - you said money no object!
9. Sportscar - Lamborghini Murcielago. Not exactly practical, but I've got a Bentley and a Range Rover for practical... and nothing else on this list has quite the same
presence as an orange Murcielago.
10. Classic - Ferrari 250/275. Blatant cop out, but my choice would depend less on specific model and much more on the car itself - glorious history and condition being paramount. OK, I know precisely which car I want, but I don't foresee Nick Mason selling it, do you?