The Nikon D700 is Nikon's, and the world's, best serious digital camera. The old professional D3 costs more and runs faster for sports, but the D700 is newer, smarter, smaller and lighter.

The D700 has image quality indistinguishable from the klunky old D3, both in terms of sharpness and at high ISOs. The D700 has the same superb 3" LCD, but handles even than the old D3 better due to a new INFO button and smarter firmware. I own a D3, and I prefer the D700 except that the D700 lacks the 5:4 crop mode I often use (most people don't care).

Even at $8,000, the overpriced D3X isn't an improvement over the D3. Sorry rich people. The D3X is the same as the D3, except that it only has the same frame rate as the D700 (maybe even a little slower), and the D3X lacks the high ISO performance of either the D3 or D700.

Unless you're a full-time sports, news or action pro, the D700 replaces the D3 for studio, wedding, portrait, nature and landscape pros, as well as all advanced amateur photographers. (I'm a very strict grader for what defines a pro; everyone else is amateur.)