I used to think I'd NEED a 35mm focal length for street stuff, but recently I've been liking 50mm just fine. Lets me feel a bit more 'anonymous'. :-)
Regarding the Heligon (and maybe the Xenon too?), I can't see any significant sharpness difference (on the computer) between it and any other rangefinder lens I've tried (mostly Voigtlanders, Canons, and older Leitz's). Hmmm...
Talk to a stranger today.
Nikon Df; Nikon 1 V3; Speed Graphic; Polaroid 250