Nikon DSLR or Canon DSLR-which one is better?

I'm looking through some used DSLRs to upgrade from my point-and-shoot. I hope to get serious about photography, but I'm young enough that I have a few years to go before I actually can. Which camera would you recommend for me? A Nikon or a Canon? What are the pros/cons of both?

It's all personal preference. This is like asking "Which is better, Coke or Pepsi?"
Ask a person who uses Canon and they'll most likely tell you that Canon is better. Vice versa with Nikon shooters.

It's difficult to compare entire brands though. The pros and cons only really apply to specific models. I would suggest trying out some cameras from each brand at a local camera/electronic shop and see which brands' user interface is more comfortable for you to navigate through.

Both are fine camera systems.

You need to look forward to see which system will work for you in the next few years, when your budget can be applied to a new dSLR

Here is a link where you can see how well the sensors of each system compare, performance wise

http://www.dxomark.com/...or-Ratings

With the move of many freelance photographers moving from Canon to Nikon, there are a lot of good used Canon cameras and lenses out there

Both have their own Pro's and Con's. No SLR camera is perfect. No brand of SLR is better than the other. So the question is, what SLR is good for a begginer? Here are some cameras that suites for ya: Canon T2i, Canon T3i, Nikon D3100, Nikon D5100.