I'm going to be using it as a "smart" upgrade to my "dumb" older TVs. They even have a version of XBMC that has been successfully ported to the Pi (raspbmc).
Other than that, it's a good tinkering and education opportunity, which is actually what it was originally conceptualized for. Very low cost & open platform that will appeal to the hacker/maker community. It's the computer equivalent of an Arduino board for many.