For me, a camera isn't cool unless it's one I'd be happy to use on vacation for 10, 12 hours a day. So right now it's the Ricoh 500G – tiny, great lens, bearable VF and flash sync at all speeds. The last one really makes it a great street shooter at night with a small flash.
For build quality and lasting design (no foam seals to scrape) however, I'd choose the Kiev 4AM with either a 50 1.8 (Helios 103?) or J12 with the Yashica 35/50 VF.
MF, I have yet to decide.