Ok Im back after a long summer of photography, and a lot of decision making. I ended up buying the D4. and keeping my D700 as backup. I got rid of my other cameras as they were rendered obsolete with the new D4.
My set up now consists of the D4 and D700 bodies, 18-35mm, 24-70mm, 50mm, and 70-200mm lenses, a SB-600 and SB-700, and a pocketwizard transmitter and transceiver with assorted filters and accessories.
I did so much debating before deciding to bite the expensive bullet that is buying the D4. I thought the D800 would do, or even just going with 2 D700's. Now that I do have the D4 I can tell you that it was money well spent. It is on a completely different level than the D700. The D800 would have been a giant mistake due to the massive pixel count. The D4 is amazingly fast and easy to use. The pictures are better than any i could produce prior to owning it. The autofocus improved on what was already the best autofocus out there. The dynamic range is spectacular. I can go on and on to why the D4 is superior to any other nikon camera (probably most if not all canons too, but im not qualified to give a definite answer as all i have shot is nikon) but I dont have the time.
And for all the pixel counters that claim the d800 is the d4 in a smaller body but with a even larger picture, you are just wrong. All you are doing is deceiving people out there that are doing their homework trying to make the best decision. After many discussions with professionals that have used both, and now my own hands on experience, there is no comparison to the quality and ease of use that the D4 brings. It is a camera geared specifically for professionals, with speed (speed to handle and shoot), ease of use and image quality in mind.
The only slight that i have towards it are the two new joysticks that wont customize to many other features than the standard, and that they removed the afc option on the front switch along with the focus type on the bottom right of the lcd screen. These have been replaced with a button to press where the af or manuel switch is. You hold it and wind the thumb dial. Its a little more of a pain, but nothing i cant get used to.
So if you are a photographer that legitimately makes a living doing photography, buy a D4, dont cheap out and get a D800 (unless your only goal is to get a great landscape shot) or the new D600, those each fall short in one area or another, the D4 is the complete package, and im excited to own it for the years to come. The shutter is rated at 400,000 shots, so im guessing ill be looking at upgrading to a D5 before that ever wears out.
Now with that said, if you just cant afford the D4 the D700 is still a great camera, I know the D600 just came out, but you will be giving up some features that the D700 has like the 51pt autofocus for 39 and the max shutter speed, along with a few other things. It does have a larger picture at 24 mp, but to me it wasnt worth upgrading. You can decide otherwise, both are great.
Jon M Photography