It is completely a matter of taste (and, some times, of types of photogharhy you plan).
Nikon was criticised for unnatural colors on portraits, but for landscapes it has a somewhat better optics that is also slightly cheaper than Canon's. The Canon's top portrait and telephoto lenses ("L"s) are much more cheap than Nikon's top-quality lenses, though. If you plan to use just a kit, then it is a completely no matter (but I strongly recommend you to purchase 40/2.8 pancake for Canon or 35/1.8 fast prime for Nikon!)
Best regards!