Just a quick list of sites and software I use to watch on-line television. I setup a HDHomeRun tuner via cable antenna, setup EyeTV 3 on my wife's Mac, and use TitanTV as the guide and remote recorder. Awesome!  Setup was nothing. Waiting for my Windows Vista MCE machine so I can get is setup and installed. I will do a compare between it and OS X, plus the others, once I get things rolling and maybe even post some setup guides. Hoping I can get a cable card for the encrypted channels. I read that the first card is free from WOW.

Let me just say, MediaPortal and Sesam are a nightmare! MythTV almost worked, but lost my settings for no reason! Seems to be a common Linux issue, at least in my experience... It really didn't well enough for me to keep anyway. So, we will see how Vista MCE does with the HDHomeRun. Either way, I watch a lot of content directly off the web saving me hard drive space and this list will should get you started. My personal favs that look really good on my LG 42" are Hulu, Joost, and Netflix. Clickstar and Blip.TV are not totally ready yet, but they look good.

CBS       : http://www.cbs.com/innertube/

NBC       : http://www.nbc.com/
FOX       : http://www.fox.com/fod/
BBC       : http://www.bbc.co.uk/iplayer/
SciFi      : http://www.scifi.com/
Sundance  : http://www.sundancechannel.com/series/
Discovery : http://dsc.discovery.com/video/

Gogooroo  : http://www.gogooroo.com/index.html
 
ShowLinks    : http://show-links.tv/
Media Hopper : http://mediahopper.com/

Hulu      : http://www.hulu.com
Joost     : http://www.joost.com/
VeohTv    : http://www.veoh.com/
*Miro      : http://www.getmiro.com/
Blip.TV   : http://blip.tv/
Peekvid   : http://www.peekvid.com/

Titan TV  : http://video.titantv.com/
Zap2it    : http://www.zap2it.com/  
Yahoo     : http://video.yahoo.com/

LocateTV : http://www.locatetv.com/

Google video : http://video.google.com/
You Tube     : http://www.youtube.com/

MOVIES (non-free)

iTunes is really good. I have an iPhone so I already use it to manage my podcast, audio, and video for my phone so using iTunes store to rent movies isn't a big deal. The player is nice, the movies look great, and the content is new unlike Netflix and cheap unlike other "on demand" rental sites. I wish I could manage my phone and rent movies with Songbird or Amarok, but you can't have everything...

GreenCine : http://www.greencine.com/main
Netflix   : http://www.netflix.com/
Movielink : http://www.movielink.com/
ClickStar : http://cstar.com
Movies-on-demand : http://www.movies-on-demand.tv/