I have heard great things about the Xigmatek Dark Knight and Scythe Mugen 2. The advantage to those coolers is that they are only $40, and in the review i read they offer better performance than some of the $60 coolers.
However, if you are an overclocking fanatic, you might want to make an investment in the TRUE or even a water cooling system.
I can't find the articles that i read, but i know those two coolers are supposed to offer great performance for their price. However you might need more depending on what you want to do. If i was going to overclock to 3.4 or 3.5, i would be fine with either of those two coolers. And that is exactly what i plan on doing when i get my i7 build