They are both quality cameras....it just depends on your preference and which lenses you already own. Personally, I started with Canon film equipment and stuck with Canon digital because the lenses were interchangeable. I have friends that have done the same with Nikon....and we're all happy.
Get a copy of the book "Understanding Exposure" by Bryan Peterson. It's one of the best photography books ever written, it's an easy read and it will get you out of the idiot modes to really get the most from your camera.
Here's a link to some of my pics taken with an older model of the Canon you're looking at:
pbase.com