Absolutely. I use mine as a media centre as well, although with the magic of WiFi I don't even need to have hard drives hooked up to it. I'm not sure what equivalent services US punters get, but in the UK we get LoveFilm and a bunch of TV stations (BBC, ITV and C4) who stream their "on demand" services direct to PS3, and there's a bunch of other music and TV related stuff on it. Blu-Ray is sweet also.
Oh, I also play the occasional awesome game on it too.
It was also the reason I shelled out on a big HD TV though, so it ended up costing me more than the price of the console, but well worth it I reckon!