I do believe the Canon XS and Nikon D40 (or D60) are equivalents! So whichever you choose you would be well off with. I love both Canon and Nikon equipment, I shot with Canon before I got my Nikon and it was great! I am however a huge Nikon fan now
I love my D80.
I got my D80 2 years ago when it first came out, it cost me $1400 total and it was on sale, but it was the best thing I have ever done! Completely worth it! It was a kit deal from B&H Photo and with that I got the Nikon D80, a Nikon 18mm-135mm F/3.5-5.6 ED IF AF-S DX Lens, two 2GB SD Cards, and a pack of generic lens filters. Definitely get at least a UV Lens filter, it helps protect the lens and the sensor.