If DBAs are how sound is measured (lower DBA, less sound), then arent the ones that ACDC ROX posted really quiet? I would get a couple though, so no overheating (I dont use my PC for anything big anyways). And will basically any heatsink/fan work on my mobo/processor, because mine is kinda odd in that it basically uses a clip or something to remove and put back on the heatsink..
its the fan that makes noise. With noise comes more CFM, so you are trying to find the best Noise to CFM Ratio. ATM Delta's have the best Noise to CFM ratio. They push quite a bit of air for minimal noise.