socket A, Hedgehog the best(ALL Copper HSF), but expensive, i say buy a Taisol or Alpha, they are cheaper and avg about 2C higher. <-- in terms of CPU TEMP 2C is alot= 4-6F. that up to you to decide.
AND also whatever you do, DO not BUY the DELTA 38CFM fan, VERY VERY LOUD. <buy delta only IF, your computer is in another room(server); if your computer has alot of internal fan and is already loud, and you just don't care.> but they are the best FAN. second probably YS-tech, also about 1-2C higher than DELTA.
well, I have a Hedgehog and Delta HSF, personally LOVE the hedgehog, Hate the DELTA, going to get ride of it. poor thing, probably with YS-Tech FAN. Temp, avg 33C, low 21C and HIGH 41C. that all folks, good luck.