Canon 5D Mark ii or Nikon D700

I will pick Canon 5D because it is great in low-light situation. Even you popped up your ISO to 1600. Lesser noise will be seen. It is a great full-frame camera.

I would choose Canon 5D Mark II. It is producing great shots and at high ISO of 12800, the performance is still great!

I'd go for the Canon but that's mainly because I already have Canon equipment. I think Nikon and Canon make equally good cameras, it's more a mather of taste.

The Canon is better, for many reasons: 5d has 21.0 million effective pixels, and the D700 only 12.1 million - If you upload photos at stock sites this is really important; 5d has starting ISO rating from 100 - and the d700 from 200; 5D is lighter only 850 grams and d700 is 1074 grams - thrust me the weight is very important if you carry with you the camera and two or three lens :) Canon is more common mark; and one more example 5D makes movie clips 1920 x1080 @ 30fps, up to 12 min and 640 x 480 @ 30fps up to 24 min, Nikon D700 does not. Well i think this is enought for now. If you have any other questions ask me and I will help you if i can. Best regards