X-rays may not be used to fit shoes.

Actually, this is a good law. In the 1950's shoe departments used to have x-ray machines (called fluoroscopes) that you could stick your foot in and see the bones. Although nifty, they gave people a nice dose of x-rays and increased the risk of cancer. Many states banned these until the federal government stepped in and completely eliminated them. Although the law sounds ridiculous at first, it's actually reasonable.

I think you want an Epia system. Epia boards can have a 500Mhz - 1Ghz processor. They are usually fanless or have a very quiet fan on them. I have an Epia-800, and after changing out the fan (it died out after a few months) I've been happy with it. It makes no discernable noise from a few feet away, and best of all, it's cheap. Everything you need is built into the board. Sure it's not a benchmark winner, but its more than enough for playing DVDs and older games like half-life and quake3. The new boards feature DDR RAM and better onboard graphics. Mini-itx.com has more info on them.