Whats the ambient temperature in the room?
I used the Scythe Ninja heatsink and my AMD64x2 4400+ never got over 40 degrees. But its too big for some cases.
I just bought the Asetek waterchill Xternal water cooler and its keeping everything at 29 degrees idle temp at 25% fan speed (it has 4x 120mm fans) so its quiet too. Playing a game like Elder scrolls oblivion with all graphics at full it never goes over 32 degrees.
I have the cpu and 2x 7800gtx cards in the loop in Sli. Before watercooling the 2 gfx cards were hitting 63 degrees, now less than half that temp.