Right now this my linux server is running in my garage. I would love to put it somewhere in the house, where I can control the dust, but the main problem with this is the noise of running the server in the house. I don't have any areas that are unreachable by our son, or where we wouldn't mind the noise. (Currently there are 4 fans in the case, as well as two drives.)
A while ago I had a G4 Cube, which was great because it was quiet. Something like that would be great, then I could keep the server in the house some where. Even thought the G4 Cube would be perfect in design elements. I did run a server on a PPC computer, with Yellow Dog Linux, and the main problem was getting installing new software. I had to build most of the software myself, and that was a pain. One major requirement is that I can install all software with rpms, so I want to stick with a Fedora installation.
Engadget has an article on a silent computer that is coming out, that comes pre-loaded with Red Hat Linux. This looks like it will be a silent computer, that has SP/DIF digital out, a PC card slot, Ethernet, USB 2.0, and a 40Gb hard drive. The one down side is that it doesn't have a cd drive, and a bay for a second hard drive.
Here are some pictures: