I <3 Distortion & Overdrive pedals.
I think I own about 11, my favourite being a Proco Rat. It's been on and off my pedalboard loads of times, but I always seem to come back to it as it seems to cut through a mix well.
Other good 'uns:
MXR Dist+
TS808 (well, a BYOC version)
EHX Graphic Fuzz

I've never really used fuzz, got a Truly Beautiful Disaster which is nice but i use more for the feedback loop.

Anyone got any recommendations on decent dirt pedals?