Thermalright makes really good heatsinks esp at keeping a cpu cool. However depending on which fan combination you choose, it can make the pc quite loud. If you are after silence, i would go with the zalman since they make one of the best heatsinks that compromise temp for quietness.
Personally i recommand, the xp120 and get a 120mm fan that pushes alot of air. Sound really doesnt bother me since i am always listening to music when at my pc