I shot at a friends party this past weekend, and brought both my D700 and D800e. I had my 28-300 lens on the 700 along with the external grip and battery pack. I used my 70-200 f2.8 on the 800. I was hand holding both cameras. My shots of the attendees with the 800 were great if they were relatively still, and I we were outside. I could reach out accross the pool and not have to shoot with the camera in their faces, and with the pixel density of the 800 crop way in to "recompose" the final print.
However, I had to switch to the D700 when people became more animated, as the shots with the 800 were blurring. I wound up shooting only about 200 frames with the 800, and 600 with the D700.
My point being, I'm keeping the D700 while I continue to refine my shooting technique with the D800. They each have their nieche.