The buffer speed is what keeps me from buying the D7000. I have bumped up against the buffer in my D300 quite a few times even underwater (esp. when trying to shoot Whale Sharks at the surface) and it has a larger buffer than the D7000. I briefly owned a D90 but the buffer limitation made me return it immediately.
The D800 might be a wonderful do-all camera, but I'm still pretty interested (at least for underwater use) in the upcoming D400 since it should be like a super-D7000 ![]()
I'm also gonna be more interested in a D700 after the D800 comes out. It will be a monster bang for the buck if they have some leftover inventory.