You might want to go to a store and check out how the camera feels in your hands. If you're not worried about how it handles (you'll get used to any camera anyway after you've used it for a while), then look at what features you'll need.
I'm a person who doesn't care about brand loyalty, but for the money, value is all that matters to me. I just grabbed a 5D Mark II, because it represents an incredible value for its price range. I've used Nikons, Canons, etc. They're all great cameras. So to answer your question, I'd probably say get the Canon XS. After all, it's almost the same as an XSi, but just a step below, and has excellent image processing. Or go for a D40, so you can save some money and grab a better lens. Here's a decent review of the D60:
http://www.kenrockwell.com/nikon/d60.htm
Personally, I like Canon's line of lenses better. But that's just me. I think Nikon's lenses are also a little more expensive (if you do similar direct comparisons).