To second what several other people have said already, think about the lenses you want to use (i.e. what sort of photos you will be taking) and spend money on those as much as the camera. If you look through 'Wildlife photographer of the year' books from say five years ago, many of those photos were taken on cameras that would now be seen as completely out of date, e.g. Canon 300D or Nikon D70. But they still got good photos! Lenses (and technique) are so important.
I'd recommend getting a second-hand camera body, and second-hand lenses as well. You can save a lot of money (enough to get an extra lens!). I'd suggest looking into prices for a Nikon D80 or Canon 400D, which are a few years old but will give you everything you need to take great photos. If you get them from a decent camera shop you should get a three or six month warrantee. This site lists places you can buy 2nd hand:
Used Cameras from 89 specialist Camera Shops in the UK
Also think about what selection of lenses you will hopefully (realistically!) end up with in a year or two's time. Some brands of DSLR have a more limited selection of lenses, although there are also 3rd party lens brands e.g. Sigma that are good - i.e. you don't just have to buy Canon lenses for Canon cameras, etc.