it's funny how the nikon guys just say "nikon lenses are better"
have you owned a canon SLR/DSLR and used canon lenses or did you just mean to say that you prefer nikon over canon?
The next time you're at a sporting event, count the number of white lenses (i.e. canon) compared to black (usually nikon) and you'll see an overwhelming number of pros use canon, and the lenses are a major reason why.
Again, nikon and canon both make great cameras/lenses, check out
www.dpreview.com,
www.fredmiranda.com, and
www.robgalbraith.com for technical reviews/forums on each.
have fun...