Lee,
This is what I use and it's a fantastic piece of kit,
very well built, easy to use and great image quality if you're prepared to tweak the results a little in software. With recent price drops it's a very good buy. However it's not as well supported as Nikon and Canon when it comes to accessories like flashes, third-party lenses etc.
Have a look at some of the general shots I've been taking on
this thread. If you mainly want to take pics at racing though, sadly I'd advise against it. Whilst it's possible to get
some okay results, it'd be easier to plump for something more expensive with a Canon or Nikon badge on the front.