Well, I have just bought an HP B1000 server, and it runs really smooth.
The box has 6 fans and the processor has a big fan with BIG aluminium disipator (I haven't seen sutch a thing even on overclocked boxes).
The fact is that the box costed me 55 euros, and only the fans cost more
also it has a PA-RISC 64 bits processor, so it's quite fast
Pics here:
http://www.icefire.org/fotos/