I will try to post a few intellectual topics. Excuse me if I insult some of you (and your superior intelligence), as I got badly flamed for talking about the new D800.
Anyway, I have the 5dII and D7k. I graduated up from the Canon 40d to the 5dII a few years back. God I loved that 40d. For me, I was familiar with the controls, feel, and AF/metering of the 40d so the transition was easy.
I got the D7000 thinking I would use it as a smaller, faster body--plus I could start using Nikon lenses on my 5d. Well, that hasn't happened yet, and I rarely shoot with the D7000. I will not take time to learn all the bells and whistles on the Nikon. It is a solid DSLR with excellent video, excellent AF, and excellent IQ. I will sell soon though. Its hard to go back to sub-FF after spending so much time with bigger, brighter viewfinder.
I like each system, though, for different reasons. I think Canon has better telephoto (and more choices) options, such as many F/4.0 choices. I think Canon produces better natural colors (leaves, grass, skin tones). I think Canon has intelligent engineers that make shooting very simple. The list goes on and on. Nikon seems to produce better wide-angle lenses. I like that Nikon has started updating all of their primes, and they are all seemingly fantastic. I like Nikon's AF abilities in their higher-end cameras. I think Nikon has better noise levels, which simply comes down to software and the processing engine.
We'll see how this next gen plays out. I was sold on the new D800, but I really want to stay with Canon as my primary option. They have a TON of news lenses due to come out, and I know they will create a great wide angle. If money was no object, I would choose the 1Dx. I think the low-light performance will be nothing short of astonishing. The IQ will be equally as impressive. Happy shooting....and shopping!!!