My favorite older film camera in general is my 1953 Mamiya Six Model V. Folding medium format rangefinder with choice of 6x6 or 6x4.5 shooting. The unusual focus system (the film plane moves back-and-forth, while the lens stays still) ensures film plane flatness.
My favorite older film
SLR (you asked two different questions, you know) is rapidly becoming the Pentax ME I picked up last week. I've only gotten one roll back from it so far, and about half of the shots are ones that my not-camera-savvy wife took with it. In addition to being friendly to smaller hands, it's simple layout and aperture-priority auto-exposure makes it a snap for even beginners to use with very little instruction. For out-and-out kewlness, though, it is my Pentax SV.
One of my first shots from the ME: