X-bit labs - Articles - High-End CPU Coolers Roundup: The Battle for Silence and Efficiency (page 16). I normally recommend the Thermal Right XP-120 which has a massive 5 inch fan, but they got good results with a smaller cheaper (e.g., less than $50) Cooler Master model.
The best cooler among the models we tested today based on performance and silence criteria is CoolerMaster Hyper 48 KHC-L91. It is not only utterly silent, but thanks to advanced design and heatpipes can cool-down even the hottest chips very efficiently. Furthermore, the KHC-L91 also boasts with easy installation.
