I was sick of the whine and bearing rattle noise the little fan in my Thermaltake GF4 cooler made, so I built a homebrew cooler for it using a K6-2 heatsink (designed to be cooled by the power supply's fan in a little compaq) and the little green 60mm fan from a stock AMD cooler. I did some drilling, tapping, polishing, and hot-melt gluing, and it works very well. I run the fan on 5 volts so it is undiscernable over the rest of the computer's moving parts.
See more pictures and a writeup on it here:
http://www.basementfreaks.com/member...4_overkill.php