A walk with my all time favourite, ever: the Pentax SMC-M 50mm f1.7, produced from the late 70s till 1984. Smooth, long focus throw, a lot of light, dead sharp, and almost as small as a pancake lens, as solid as a rock. Good for almost anything, I use it for portraits and objects. Color rendition is among my favourite. I’d prefer this piece of lenses over everything else in my collection, including the new electronic ones.
The only negative thing, if any, is the focal length that on a 1.5 crop body matches the equivalent of 75mm on a 35mm sensor, but that is anyway due to the body and not the lenses itself.