I bought a D800 shortly after they were released, having owned Canon DSLR's for years. I still have a 5D (original), and many Canon lenses, hoping they will release that killer model (still waiting BTW). I don't regret buying the 800 one bit; it's the only body I've used since I purchased it. At the same time I bought the 800, I bought a 14-24. The 14-24 is a really fine lens; one that Canon doesn't have an answer for.
Yes, the DR is very nice to have, and is quite a noticeable improvement over Canon. The difference between 24mp and 36mp is not as important or noticeable as you might think though, so I would not make that a prime consideration in your decision.
I usually leave the D800 in auto ISO mode, and shoot all the way to 6400 and get great results. No, you probably don't want to shoot landscapes at 6400, but overall, the noise performance is excellent.
Nikon lenses do seem to be a bit more expensive than Canon, though Canon seems to be trying to catch up.
Good luck in your decision.
Thanks for all the great info here. I think it would be prudent for me to wait until Photokina is midway through to see if maybe even Nikon is going to best themselves.
I am having a hard time picking a super wide angle zoom from Nikon. There seems to be no less than 5 choices by Nikkor in the 14-35mm ranges. The 14-24, 17-35, 16-35 X2 , 18-35.....which one, in your opinion, is the best for 100% outside shooting. I have been quite happy with my Canon 16-35 2.8
DXO Mark rates the nikkor 14-24 very highly, perhaps a bit wider than i want and no option for filters.
Any input in this area would be appreciated.
I am pretty sure I am done with Canon after so many years fighting the autofocus, and them not caring. I am sure that some people can complain the same about Nikon. The problem with Digital is that we are so much more reliant on the technology of the Camera than we ever needed for film. I was happy in full manual with my F3's and sharp as hell glass...it is nice to not have to wait for the mailman to bring me my Kodachromes a week later, but I do miss the simplicity of the old ways.
All the best,
Axel