Quieter fans (probably):
http://www.tomshardware.com/forum/56...iet-120mm-case
I have had 120mm Vantec Stealths for a decade in cases with any 120mm
fan mounts. They are pretty quiet. (The jury-rigged 40mm Delta that
I used to replace the anemic OEM fan on top of the heat sink on a pIII
makes more noise than 4 other, larger fans in the same case all
together. That pIII still works, though.)
I see from that thread that there are some newer, quieter 120mm
offerings now.