What I am trying to say is very simple:
Nikon is slow in development and even the long time they take to come up with somehow decent products does not help to really improve over the competition. And BTW - you really should look into Canon documents, then you would know that the 1DSM3 has sensor cleaning. And this since over a year already!
I shoot with a D3 myself and while this camera was a real milestone, I expected the D3X to bring at least similar improvements after this year of development. But obviously Nikon is hitting the wall with their digital technology again. Canon is already far ahead.
Take it as you like - I am no longer convinced of Nikon becoming the leader again.
Ok, I've watched the video, so the 1DsIII apparently has dust removal. Just four years after the Olympus E-1. I also found that the Mark III has ISO in the viewfinder, as opposed to the Mark II, something I believe pro Nikon cameras have had since the D2H in 2003 (this according to dpreview).
We can discuss features of camera bodies for weeks without getting anywhere, and it doesn't really matter. I'm sure I can take the same photos with any of these two. Lenses, on the other hand...
The one camera that really stands out, is the A900. It has all the megapixels, sensor cleaning and in-body IS, all for well under half the price of either the Nikon or the Canon, and it mounts Zeiss AF-glass, zooms as well as primes.