I currently have a OM-2 and I used to have a Canon F1N as my main camera.

The Canon is a great workhorse of a camera. Not overly large like a Nikon F, but solidly built and heavy to match. (the motor drive, on the other hand, is humungous)
For some reason the sound of the shutter really makes a difference to me, and the F1N was music to my ears.
Both systems have a wide variety of lenses, but the FD system seems to be more available at the moment.

One really nice feature of the OM2 is the big, easy to use exposure-compensation dial.
The camera is small, as well as the whole system. I have a body and 3 lenses in a bag that only fit the Canon and one lens.
The faster OM Zuiko lenses tend to be pricey, but the basic 3 lens kit (28mm f2.8, 50mm f1.8, 135mm f3.5) can still be had cheaply.

I have a 50mm f1.4, 24mm f2.8 (great lens!), 85mm f2 in my usual kit. I also have the 135mm f2.8, 35mm f2, 28mm f3.5.