If we're going on what have I re-watched the most times in my lifetime, it would have to be either Tenchi Muyo, Trigun, or Cowboy Bebop.
However, if I rewatch anything, it's usually whatever flavor-of-the-month movies I enjoy that are on HBO/Showtime/etc. Right now it's Scott Pilgrim and How to Train your Dragon, a couple months ago it was Toy Story 3 and Avatar, and in about a month or so it'll be Inception. I usually only have the TV on as background noise when I'm doing something tedious in a video game, like 90% of WoW before I quit, so I tend to leave it on things I know. In the grand scheme of things, I don't typically re-watch things, and when I do only in a great while.