Originally Posted by Peter Jennings
Whichever camera you choose, pair it with a good external finder like the ones from Leitz or Voigtlander. They make framing easy and pleasurable.
I second this. An external finder makes things a lot better with a Barnack. Aside from the obvious benefit of having a much better finder, it also lowers the camera so it doesn't hide your face, which I think is less disturbing for the people passing by.
Secondly: It is an RFF tradition to suggest an entirely different camera than the one being asked about. So: how about a Minolta CLE with 40mm or 28mm Rokkor? You will get auto-exposure--off the film, no less--and a better viewfinder! And a 40 or a 28 is better than a 50 for street work. Of course, it's not a Leica . . .