The old full frame vs cropped sensor debate always comes into buying a new camera. I did a lot of weighing things up before getting the D300s, borrowed a D700 for a little while too.
As much as I love the D700, for wildlife photography it wouldn't cut it for me. The extra reach I get with my lenses makes the cropped sensor a much better option for me. Also using a full frame camera for macro shooting would be a bit of a pain. I'd have to crop the image substantially to get as close as I would have with the cropped sensor. If I was working in studio environments more, I may have very well gone the D700. The low light capability is kickarse
But then again, the low light capability of the D7000 isn't all that far behind some of the full frame cameras. Things are catching up.