If you want truly Pro, look at the Nikon D4 and the Canon 1D.
Go into a real camera shop (not a big box store) and ask to see them, pick them up and see how they compare. Pick the one that feels the best to you and works like you want. Unless you know of something that is critical to you, don't worry about the features. These are both top-of-the-line cameras. Both will do quite well for you. The important thing to me is how you make changes -- f-Stops, shutter speeds, ASA, light temperature, bracketing and the like. Both cameras are very fast to start up and to respond from idle.
I will admit I like one much better than the other -- it is simply because the menu and how to change the settings outside the menu is more intuitive to me. It works more like I think. You will have to determine which one works the best for you. (The one that works best for me is immaterial.)
That said, the Nikon D800 and Canon 5D are also great cameras. Don't compare the D4 and the 5D or the 1D and the D800 -- the comparisons are not fair to either. If you have the money, look at the D4 and 1D and go from there.
And then there are the lenses. Picking them out can get to be even more fun.