Nikon for SLR's. They have better lenses (which is ultimately where most of your money will be spent).
D60 is a great camera. I currently have a D40 that I will likely upgrade in the next year or 2. I love it, it takes fantastic pictures.
If I were to buy a camera solely on the range of glass available, I would definitely go with Canon - they have a greater selection, and L series lenses are incredible. I got a Canon entry level SLR when Canon where ahead in the market, so to speak, and my preference hasn't changed since then, with further experience and research. As
auroraskye said, the debate between the brands is only really relevant at the higher end of the SLR range. One thing I have to say, is that a camera alone does
not take fantastic photos - it needs to have a good photographer behind it. I've taken great shots on a point and shoot and an SLR alike. My point is, having a quality camera isn't the only thing to taking fantastic photos, and your photos will not automatically be better for having an SLR. Phew, now that's off my chest, I feel better
Anyway!
For future reference, the XS is also known as the 1000D, and the XSi is the 450D
Between the two, I would definitely go for the 450D. THe 450D has 9 focus points to the 1000D's 7, a slightly faster frames-per-second rate ( speeed
), the option for an infrared remote, which the 1000D lacks, a larger screen, and the option for "live view" when shooting, which is handy for someone moving to an SLR from a point and shoot.
This is a comparative test between the 1000D and the Nikon d60, and
this is the same test between the 450D and the d60. Between the 1000D and the d60, there's not a great deal of difference, so much so that the reviewer states that, between these two cameras "it comes down to personal preference which result is better" ( quoted for truth ). Between the 450D and the d60, though, there's a notable difference, with the Canon capturing more detail across the entire frame. Hope this is helpful!