I consider a grip for all my Nikons because I like a substantial feel in my hand when I am shooting. On my D70, my pinky has nowhere to grip, until I put a grip on. On my D200, the grip was $175 and I bought that along with the camera on the same day.
The D700 body alone is too small for my hand, without a grip. But, I have a problem justifying the $300 for a grip, even a Nikon grip. It is not the money, it is the gouging that I despise.