I'd go with the Xbox. Mine boots in about 16 seconds (not 30 - 90 for a PC). It networks with my other Xbox with no problems at all. No drivers to mess with. They were made to hook up to TV's, the games just work (no messing with configuration, drivers, version'itis), etc. etc. etc.
I play the snot out of mine. Check my thread on the Xcelerator below if interested in my Xbox driving cab build. One of these days I'll finish the side art and call it done.
Good luck with yours.