i modded my old Xbox for 15 euros, the chip was a press on, didnt even need soldering,
put in a spare 120gb IBM drive in it, it played most video and audio codecs, gut shoutcast radio support, played mame, nes, snes, n64, genesis, master system, atari 2600, playstation 1 games, the shortcommings ? no DVR,
but i could manage the the drive as a samba share or trough a FTP server on the xbox, there are several "ready to load" DVD images which basicly in 30mins leave a XBOX ready to do more or less alot of the functions of a HTPC, the only problem is that i think that the original XBOX was limited to 480P, but it was nice, i could even store my xbox games on the harddrive, so i wouldnt have to change disks when playing,