Wouldn't I need to have the media on the Pi to do that? I'm a bit of a documentary and music video hoarder, and have about 3TB of them :-)
I also use it to stream internet radio, which is nice, but it can be a rather random cornucopia.
It has about eight different types of input, of which I use two (I don't watch broadcast TV). I need to investigate the other six, I suppose.