Converting a Garage into an Arcade?

The ever curious AtariDatacenter asks: "I'm finally going to get my wish, and upgrade my two car garage to an 80's style arcade room. I've found some good ideas in the RGVAC newsgroup. But for those who aren't hardcore into collecting, what are major aspects of an arcade gameroom that you'd put into your own home? Would this make a home more or less marketable?"