I have a Leica M6 from 1985 and a Hasselblad 500 CM from the 60’s that are both in incredible condition (after a recent CLA). They are wonderful machines, especially the Hasselblad (each piece removable, serviceable, swappable)
I would love an old M film camera but I have no idea which one I'd want to get. I have a M10 and a M10 Monochrom today and love them!