Johnny Depp?
Seriously, if there's an "eccentric" role to be played, no big deal, we'll just get Johnny Depp to play it, right? He's weird, he'll do it, right? But when it comes to actual acting, can he do it? Not so well. Sorry, the man is extremely over-rated.
My vote goes to Nicolas Cage.
Also think Depp is terrible.
Gerard Butler = Daytime soap level actor.
I don't think Nicolas Cage would've had the chops for Hollywood if he wasn't a legacy (he's Francis Ford Coppola's nephew, I believe?)