Arctic Cooling Freezer 7 Pro CPU heatsink
 

A good, silent, cheap CPU Cooler, does it exist? The Freezer 7 Pro from Arctic Cooling comes close:

"Overall the size and weight of the Freezer 7 Pro make it a good choice since it is not over 600g. The heatsink is also guaranteed for 6 years, which is longer than most system lifetimes! The fan is very quiet and does have a PWM signal line so that the motherboard can control the fan speed and further reduce noise

http://www.gideontech.com/content/articles/343/1