I know some of you out there love ABC's Lost. Well you can now stream many of ABC's shows (CBS as well) from their web-site. I don't have the CBS link, but I've tried ABC and it's pretty slick. They drop some of the commercials and you can get a rather large, good quality, wide-screen version of Lost, Alias, Desperate Housewives, etc. on your computer screen. Not sure how many episodes they keep up there, but the most recent ones for sure (I hear they may have all the Alias).
Click the title for the ABC page.