I received my D700 today and after throwing in my EN-EL4 pack from my F6, was off to the races setting it up.
I haven't gone shooting with it yet (I am waiting until closer to dusk), but have tested my 70-200 VR lens on it. As I was expecting, the corners darken quite a bit wide open. You can actually see the effect as you zoom from 70 to 200mm in the viewfinder. I shot RAW + jpg and turned the in-camera vignetting control off to see how bad it is. It is rather bad I have to say. It is too bad as this is one of my favorite lenses.
I plugged the NEF's into Capture NX 2 and used the vignette control in the software to see what I could do at both 70 and 200 mm. The correction worked better on the long end, which is good since this is where I use the lens most.
While the software fix works at least reasonably well, I think I will be using this lens mostly on my D2x instead of the D700.