When I used 35mm SLR, I shot with minolta SRT102 bodies (four of them) for the first 15 years of my career. When I could no longer get reliably nice professional grade lenses for the MD mount bodies I moved to Nikon FM2n bodies, then F100 then D100, D2h, D70, D70s, D200...etc... Now I make my living with Nikon, carry a Canon point and shoot (SD700IS...maybe soon a G9) and use Leica and Rollei for fun.
I did use an OD green Canon F1 at one duty assignment in the USArmy as an 84B10f (Still Photo Specialist) and it was OK, but mostly I prefered my minoltas because I knew them more intimately.
The only reason that I chose Nikon when moving on from minolta is that Nikon had maintained the F mount and was the only company still making professional mechanical cameras along side the AF wiz bang bodies like the F100/F5 and with the promise of DSLRs on the horizon also all taking the same lenses. Given the FANTASTIC tool that iTTL / CLS is, I'm happy that I went with Nikon. (Though, Canon DSLRs are pretty cool too and ETTL II is gaining ground.)