I once had a plan that if I ever went out of work and needed to get some money; I'd build small, inexpensive Linux boxes that could provide the home or small office with everything they could ever want - lots of space for file sharing, printer sharing, with a built in switch so it could do broadband routing as well. It's a shame that it's already been thought of, here: http://www.quadmicroworks.com/squareone/features.html

Hmm, pretty cool, looks just bigger than a Mac Mini.