[Rapiddude]

I own the original Canon Digital Rebel. It's a great camera. Nikon was slightly superior the last time I had an opportunity test both at length, but that was when I was working at a camera shop two years ago.

Go to a camera shop where they will let you play with both for a bit, and see which feels better; use as many features of each that you can. If you have a film SLR, you may be able to share lenses if both are built by the same company (I'm sure about that with Canon; Nikon, not so much). The cost of the glass may be the deciding factor.

Software is not something I would strongly consider when choosing a camera; both companies have decent software, but it's not critical. I move files with Windows Explorer, and fiddle with them using Paint Shop Pro; I stopped using the software years ago.