In this review the boys at Frostytech compare the Glacialtech Igloo 5610 Silent heatsink against a hundred other low noise heatsinks. Is your PC running quiet enough?
"The Glacialtech Igloo 5610 Silent heatsink is identical the Igloo 5610 PWM model in all ways, except that the two coolers use different fans. The Igloo 5610 Silent that Frostytech is testing in this review has a nice and quiet fixed-speed fan, the previous model a louder PWM fan. Both heatsinks are compact LGA775 compatible CPU coolers and suitable for office PCs.
Glacialtech's Igloo 5610 Silent is a simple heatsink, economically priced and quiet running as its name suggests."