Shuttle SD11G5
 

Link
http://www.bit-tech.net/hardware/200..._sd11g5/1.html


Quote
"The system is exceptionally quiet. Companies will often market silent this and ultra quiet that, but this thing is leaps and bounds ahead of every other powerful system I've ever used. The problem you will encounter with this rig is that it is so quiet, other noise pollution coming from the system (eg video card, hard drive) is easily noticeable."