My formula that's a result of empric selection is 1 body (LX or MX), 50/1.7 (80% of shots), and 16/2.8 Zenitar fisheye (when I need *really* wide). Often together with 135/3.5 and 24/2.8, but these are much less used, and lately 24 has seen less and less action. Together with a bogen table top tripod, it all fits in a small Domke satchel and is very carriable-around all day long. The rest of the gear is being used when I know beforehand I'll need it. Which doesn't happen very often.
Best, Mishka

