Globalwin FOP-32's for both systems, but with the supplied YS-Tech fans removed and fans from CoolerMaster DP5-6H51 heatsinks substituted. The fans are ran at 7.5 volts to further reduce noise.
Suprisingly, this has little impact on the cooling ability of the heatsinks. Both systems run very coolly.
I'm going to purchase a couple of silent drive enclosures soon too. It nice having a fast system, not so nice having the aural equivelant of a mini jet-engine idling in your home.
Greg