Mark has it- I am going through this right now. All set to get a D700, as I needed another body-- The 18-200 fast became my sort of walk around lens on my D 80. I am still more than a little PO'd that this lens will not work in full with the D700. I have for the most part gotten over it and will just leave it on the D 80. Thing is, Ken Rockwell suggested that there may be a D700 X out between now and the end of the year? Who knows with Nikon?
What the improvements might be over the current offering is anyones guess. Built in VR is one guess, and for me that would be worth the wait, again, we are guessing here. Still need to make up my mind.