I know this thread's half dead, but... just because it needs to be seen:

http://www.colour9.com/gallery/view_album.php?set_albumName=album17

http://www.colour9.com/gallery/view_album.php?set_albumName=album98

...this is how you make a very, very quiet PC. I've got it down to one fan (in the power supply), everything else is passively cooled by the big wrought-copper radiator.

It's not the most economical solution (the labour time alone makes it shockingly expensive), but then I've always preferred over-engineering wherever possible :-)

Oh, and I've also water-cooled my server box:

http://www.colour9.com/gallery/view_album.php?set_albumName=album96

Now I just need to find a way of squeezing the pipework into a mini-ITX case and I can water-cool my MythTV setup...

Gavin