I've seen the SilentPC site but their reviews i find are few and far in between.
They have some great tips on silencing issues though that i've used on my system.

Next two major changes towards silence include adding a water cooled system but using a quiet, slower pump not really for high end overclocking (e.g. the Zalman Reserator).

Second, moving to SSD for storage.

The two loudest components in my system are:
CPU fan (just using stock for now)
HD data seeking and platter spin

Otherwise my comp is almost dead quiet.

"Those who preach the myths of audio are ignorant of truth."