Remember - the body is often the cheapest part that you have in your collection after a few years. The decision between Nikon and Canon is a decision between two different systems of lenses, flashlights and all that other equipment you need. Every system has it's good and bad things and the more you read about the whole system, the more you will know which body to start with.
E.g. I do like the concept of the usability of Nikon Bodys. Most of them feel better to me than Canon ones do. They also have a different philosophy of how images are already changed by the body itself - leading to "softer" pictures with less noise at Canon, and "sharper" pictures with a little more noise at Nikon. Nikon also seems to give the photographer a little more responsibility for the pictures with less "automatics". On the other hand, Canon has a little cheaper lenses and the IS on the teles is a brilliant thing.
Of course, if you ask a different photographer, he will tell he the complete opposite of what I told you - so the best thing is, don't buy anything at all.
So long story short - think twice about the body, but think three times about how you like the whole system. You will still use good lenses in ten years - the body will change.
Greetings