IIIc with a collapsible Elmar 50/3.5, and from among the following:
- Jupiter 3 50/1.5 - the most compact really fast lens I know in LTM.
- CV 35/2.5 Color-Skopar
- CV or Canon 28/3.5 lenses - for this and the 35, get the CV 28/35 finder - it's wonderful
- CV 25/4, 21/4 or 15/4.5 depending how wide your taste ranges.

I myself would go with 15/28/50.