This is a home theater PC I built from mostly spare parts. It was designed to be as compact and quiet as possible, given the parts I used, and also not look intrusive in a living room setting.
I recently switched GPUs from an HD3650 to a 9800GTX+, and because I also have an old 8500gt, I now have two nVidia cards. This means that in Windows Vista, I can run two video cards (Vista requires the two cards to use the same drivers, but W7 does not). To get the setup working, I had to do some modifications to the 8500gt, as well as build a stand for my monitors, since my desk is too small for three.