SuperRock: Spire 5T208B1H3T
Of all the Rocks, the SuperRock has the smoothest underside. This takes another big chunk out of the heat transmission resistance. Its base surface measures an impressive 70 by 74 millimeters. If that's the cooler you'd like to get, you should first measure your board to make sure that no capacitor palisades get in the way.
The profile of this base plate varies in the shape of waves, too - the plate is thicker in the center, then the material gets thinner before thickening again towards the edges. The thickness of the fins varies similarly.
As as result, it cools almost as well as a copper cooler.
It almost goes without saying that the cooling capacity of this mega cooler is extremely good. An Athlon XP 2000+ has no problems keeping its cool underneath it. There's plenty of thermal leeway for overclocking or for a faster CPU.