I second everything F5fstop said. I am a Nikon junkie big time. Even down to their point and shoot coolpix line.

Myself and my GF are both also semi-pro photogs. We both do landscapes, abstract, architectural and fine art nudes (studio).
She was a Canon Girl for many many years. Recently she got rid of the Canon gear and bought a Nikon D200. She was blown away with the colors she is seeing out of her D200. She loves it!
I shoot with my own D200 or my D2H. I sold a D100 for the D200. I can't imagine *not* shooting Nikon.

One aftermarket lens to consider that I didnt see f5 mention is Sigma. I have a couple Sigma lenses and I really like them.

@f5- nice posts! very informative!!


EDIT: forgot to add, if you think you will be doing any flash photography (on camera and slaves- not studio strobes or hot lamps), Nikon is widely considered to have the best flash system out there. Having played with my SB-800 master on the camera and the SB-80 or whatever the model number is as a slave, I can say I agree. Amazing results are there to be had.