I'm a long-time Nikon user, but recently I've been using my wife's spare EOS 35mm body, a Rebel XSn, with a Pentax screw mount adapter and a Super-Takumar 55mm f/1.8*.
Compared to my F3 and MD4 motor, this camera is very quiet. I can't say how it compares to other Canon EOS cameras, but my F3 is like a gun going off compared to this little camera. It's also very lightweight. Finally, the 35mm Rebels are super-inexpensive these days.
*I suppose some of the reduction in noise has to do with the fact that both the focus and aperture are totally manual when using this lens.