ok,, are you asking about the D7000? and not the D700, I agree with the responses above for the D700, but if the question is on the D7000, then I say the D7000 will compliment your D800 for Photo quality and Video ability. The 7000 has dual slot like your D800, tough build.
You might consider the 7100 instead for a few more hundred, but I understand the Video is improved even more, plus like the 800 has the 51 point of focus,
so,, the 7100 is kinda like the small brother of the 800.
I own the 7000, 700 and 800,, I tend to use the 800 and 7000 more then the 700.
not to knock the 700, capaple camera, and produces wonderful still images.