Where are you looking to go with your photography? Shiny new gear is always nice, I admit, but there are loads of options open to you.
You can buy new - D80, D90 or D300. If speed is not of great importance, a Fuji S5 Pro is a fantastically well-regarded camera.
Or you can buy used - plenty of dealers, or privately. The D80 is still a good camera, as is the D200 (Aperture had one recently at £330, Park has one at just under £400) You will get more creative control at your fingertips, and save a packet in the meantime.
That's the way I went, from a D50, to a D80, then D200 and now a D300...