Solema

You asking me, Mathews? I'm using a Thermalright Ultra-120 Extreme, currently one of, if not the best, air coolers on the market. I used to use a Zalman on my FX-60 rig, but they are geared more toward quiet, effective cooling than all-out performance. With the Ultra-120, you can use any 120mm fan you want, and the Scythe S-Flex SFF21F is what many people, including myself, use. It's an awesome combo and lets you push the CPU pretty hard.

But yeah, NEVER use stock cooling if you plan to overclock. Also use Arctic Silver 5 thermal paste instead of the generic stuff. It can make a difference.