HDMI
VGA
RGB Scart
S-video
composite
coaxial
There is also component which would be same level as VGA, although some are considered 'better' you won't actually see any difference.
There are a few WMV-HD films out which are designed to run on PC's or a few specific DVD players - hardly any choice though. Asia has HVD's not sure how much stuff is out though.
Also D-VHS which came out years ago in the States and has been discontinued.
The main source of HD films is from US broadcasts which have been ongoing for years, they are captured via firewire to PC and then made available to download - obviously those aren't entirely legal so I know nothing whatsoever about them other than what I just posted.