i use a canon EOS40D and love it with all the love that isn't reserved for my laptop and sharps! although one of these days, i'll be having an EOS7D. i'm prejudiced against nikon because i had one of theirs when i was 12, and it broke after 3 days. i switched to canon, and never looked back.
that said, it's ABSOLUTELY the glass in front of the camera that does the important job. pick a body that you like and works for you, whatever price, but get the highest quality lenses and filters for it you can afford. i made that mistake, but i'm going to start putting it right soon with a sigma 18-50mm f2.8.