Every modern SLR has several exposure modes:

Program - full auto selection of shutter speed and f-stop, some cameras allow you to turn a dial and shift to equivalent exposures
Shutter priority - manual selection of shutter speed, camera picks the proper f-stop
Aperture priority - manual selection of f-stop, camera picks the proper shutter speed
Full manual - self explanatory

There are other assorted modes but those are on basically every SLR. I'm partial to Canon cameras myself for a few reasons. One main reason is that Canon builds the motors that focus the lenses into the lenses themselves, instead of having the motor inside the camera itself that drives the lens through a "transmission" of sorts. They're about 10 years ahead of Nikon with the development of their auto focus chips as well. I have a Canon EOS A2 (it's since been replaced by the EOS 3) which came out in 1992 and can still focus faster than an N80.

The zoom lenses usually included in the package deals are kind of crap and they don't give you a very wide maximum aperture which is kind of a pain when taking action shots which is I presume why you want the fast focusing and motor drive speeds.

What kind of pictures are you trying to take and why do you think you need certain features?