I'm not sure how many follow the DXOMark tests (or even agree with them), but they seem to be a great influence-r in the still camera world.

What they have 'discovered' is that the D800 sensor is the best, even better than the $40,000 Phase One IQ180 digital back. Here is their report: DxOMark - Sensor performance (http://www.dxomark.com/index.php/Publications/DxOMark-Reviews/Nikon-D800-Review/Sensor-performance)

The highlights are:
1. The D800 sensor has the highest dynamic range of any camera, at 14.5 stops - obviously it's hopeless to expect this performance in its video mode but it will help.
2. The ISO performance of the D800 is equal to that of the D4. That's incredible. This does not mean that they will match aesthetically, of course. In fact, I have no clue what this result means if that is the case!

What's interesting is that the 5DIII results are yet to be released. Can't wait for the video reviews of both cameras to start pouring in.

Just don't get your hopes up too high for video performance:

Nikon D800 first Hands on Morié effect RAW clip 720p - YouTube

I really don't see how the ISO performance can match a sensor with pixels more than 50% larger (the D4).

This 'performance' score really ticks me off because the D800's sensor is made by Sony and Sony agreed to not use their sensor in one of their cameras for an entire year. In the meantime, Nikon is selling probably one of the highest demanded cameras EVER! (this doesn't mean the highest *number* of units sold, but the most sought after camera in which there isn't enough supply to come anywhere close to demand. This camera is greatly back-ordered and will be for some time)

I love shooting stills with the Sony A900 and Zeiss glass, but I currently use a 5D MkII and 7D and I hate the 5D MkII's ergonomics and menu system. Canon is the ONLY camera that doesn't have an Auto ISO Range. From what I have read, Nikon's Auto ISO Range is the most adjustable and the D800 has an upgrade to the adjustments. With the Sony A900, I can set the Auto ISO Range to automatically select the ISO between 400-1600, for example or 100-800 or 200-1600. For fast paced events like weddings, this ISO range makes a huge difference.