Literature: Iago. Got to read his parts in English, and It was sooo much fun. Many of my favorite villains are manipulators, and no one fits the bill better than he.
Film: Vader. "Apology accepted, Captain Needa"
Video Games: Darth Traya. See above: Manipulators. Saren Arterius gets honorable mention, along with the Man of a Million Girlfriends,
TV: That bastard Joffrey. So very punchable. oh, and Moriarty from Sherlock. Almost forgot about him trying to not think about that show until October.