Coolermaster Hyper 212+ cpu heatsink. The universal cpu retention bracket uses screw down fasteners. Performance is very good. Best bang for the buck. I have an original Hyper 212 in my personal system.
^+1 for the Hyper 212+. I've got the Hyper 212+ and it works great. Other heatsinks may do a better job but they cost quite a bit more and probably aren't worth the extra cost unless you want to do some extreme overclocking.
I just installed a Megahalems last night, and temps instantly went from around 80deg under full load to around 50 deg. Never higher than 53. That was using Scythe Slipstream Kaze-Jyuni 190 rpm fans in push-pull and arctic Silver 5!
Rusty_M - At an ambient air temperature of 21 degrees Celsius my cpu core temps do not go above 50 degrees at full load either - that's with my Hyper 212, IC Diamond 7 Carat Thermal Compound, and just one Scythe S-Flex 1600 rpm fan.
Also, Prolimatech recommends 120mm fans between 1200 rpm and 1600 rpm for optimal performance - 1200 for casual gamers and 1600 for hardcore gamers.
maybe I should turn those fans down a bit and enjoy the reduced noise. They certainly push a lot of air. They are 120x25mm though. I also think my ambient temperatures may be quite high, although there's no thermometer in my home.