Canon or Nikon? This is the question that no one has been able to answer since the dawn of time (note: time started in the 1930s). I think most of the photographers think answering this question will prove them to be fools because one of these companies wins the battle over the other time after time, but (and a very big BUT) alternatively. When Nikon declares D700, Canon announces 5D Mark II- which, in fact, is better. When Nikon again declares a better model- D800, Canon promises to deliver a mighty 5D Mark III (and they delivered).
So which one? Canon or Nikon?
Consider this: Nikon delivered the lenses for the early Canon cameras. Canon seems to have forgotten this, and shows no sign of gratitude.
If you want me to sum it up in three lines, I would say it like this:
"Canon and Nikon don't give a damn about manufacturing your dream camera, because none of them considers manufacturing cameras as their main business. Canon is an optical-electronics company which makes cameras, Nikon is a lens company which makes cameras. You get the picture here."
Personally, I have used both Nikon and Canon cameras for a significant amount of time. I think the Nikon lenses are better, and the operation of the Canon cameras goes more smoothly.
You will hardly notice any difference in the image quality. As I said, Canon is an optical-electronics company, the noise performance is better (somewhat). On the other hand, as Nikon is a lens company, Nikon images are sharper (somewhat).
Which camera will you buy?
If you don't have much money, go for the Nikon D3200. If you have money, and want a full-frame camera, go for Canon 5D series. If your financial situation is in between, buy the Nikon D7000 or the Canon 7D. If your dad is Donald Trump, buy a Leica M9 Titanium.