The Corsair's are also made by Seasonic and, I agree, are very quiet.

For my main rig I have a couple of SilentMaxx/Alphacool PSU's like this...



Link

I don't like the block design (fairly restrictive)so I'm replacing it with a mosfet block. The block is just bolted to the end of a heat sink that protrudes slightly out the rear. Even if it leaks, no water will enter the PSU chassis.