You let go a Leica M3????
Well you can't go wrong with a Nikon F. I have both the early eyelevel prism and the later Ftn meter head and both are tanks. I dropped the later one by accident onto a concrete floor, the filter broke, so did the concrete, and the meter had to be fixed. The lens was fine and so was the rest of the camera. I have grown to like the Nikkor 50 f2; the 50 f1.4, 105 f2.5 and 35 f2.0 lenses are in my opinion, classics.