I would put a 2nd vote for PLEX, at least for HTPC/PLAYBACK (doesn't have any Tuner level access say like XMBC, etc). Does have some web-channel playback (discovery, etc).
I have it running at home.. by far one of the simplest to set up.
Great playback support 2.0-5.1 full playback, have thrown just about ever video format at it fine.
Playback as stated above, on MANY devices, its built into my LG TV.
Only downside, is yes having to download it all manually for it (or like stated above, use some forms of automated programs)