Speeze CPU Fan Model 5F263B1M3 for AMD/Intel Socket A/370
Very quiet and an excellant cooler.
http://www.newegg.com/app/ViewProduc...tby=14&order=1
http://www.newegg.com/app/Showimage....150-010-04.JPG
Also if you really want it to be as quiet as possible, switch the bladed case fans out to 12volt blowers like the one at the link below. They are not as efficent as fans so you will need a couple of them, but you cannot hear them run.
http://www.radioshack.com/product.as...5Fid=273%2D199