Screaming Penguin - Source Does Matter

"Your internet television has arrived" is the marketese and basically it is fairly accurate, Democracy.tv is quite good.

For the uninitiated it is an open source, cross platform capable, interweb based video guide, recorder and player. The guide/recorder part is what is significant (IMO). You have an extensive channel guide/recorder with access to all sorts of content (600 default channels at current, mainly creative commons independent stuff, some good/some not, but a little bit of everything) and you can add any feed based source (including torrents).

0.9.0 is now available for Windows, Mac and Linux.