Well, obviously the factual answer is ZP. It brought me in, and probably 90% or more of the rest of traffic too. Now, I voted for Extra Credits, because I think it's the finest segment on the site to date and is a great exemplar of everything The Escapist stands for - thoughtful analysis for passionate gamers. But if it came right down to it, the one show on ESC that I could not live without... that's Doraleous & Associates. God dammit, if those guys aren't working on a D&A movie, I'm gonna kill 'em, because not having D&A in my life makes it barely worth living. That's a slight exageration, but still.
DAMMIT NEEBS
EDIT: At the end of the week, tho, Movie Bob is the first thing I watch. He just isn't quite as relevant as EC, but he is my favorite commentator on the site.