I don't know yet! I've always had an interest in planes and helicopters but I've only just found myself in a position to do anything about it, so I'll tell you in a few months if I'm really a prop head or not!
Aside from that, always had an interest in fast cars and dabbled a bit in go-karting, but I'm board of the restrictions of the tarmac and potential for accidents. Like FleetFlyer, I'm a control freak as opposed a speed freak though.
I like watching all sorts of sports - motor racing of various guises, football, cricket, rugby etc, but don't participate. Used to play a lot of badminton but have recently converted to tennis which is the exercise I use to justify consumption of beer, which is my other main hobby!