No Xbox You can modded, but still wanting to use this beautiful piece of software: XBMC ?
You may take a look at the Media Portal
"Media Portal turns your PC in a very advanced Multi MediaCenter / HTPC.
It allows you to listen to your favorite music & radio, watch your video's and DVD's, view, schedule and record live TV and much more. You get Media Portal for free/nothing/nada/noppes and best of all it is opensource. This means anyone can help developing Media Portal or tweak it for their own needs!"
It is using a regular PC architecture and has more possibilities like MPG recording, TV (PVR). It cost also a lot more too, but it is still less expensive than M$ media center 2005 and is not cripled with Digital Right Management (DRM [wikipedia]) technology.