AL Tech MediaGate MG-25 Portable Media Center
As you may have guessed, this is more than just an external hard drive. This "MPEG4+MP3 jukebox" allows you to store images, videos, and music on the internal hard drive, organizing and playing them back however you like. It's significantly cheaper (and smaller) than any HTPC and with the exception of games and the possible use of applications, can do all the same things.
And here's the link: