I've mentioned the Adam Sandler thing a few times before on here, but the thing that annoys me most about him, even more than the fact that 99% of his movies are awful is the fact that he CAN actually act. Just watch him in Punch Drunk Love or Reign Over Me.
As for Owen Wilson. Watch him when he's being directed by Wes Anderson. It's like he's a completely different actor. Thought he was great in Midnight in Paris too.
Vince Vaughan? Good in Swingers, Thumbsucker or Into The Wild. Made an awful lot of garbage otherwise.