Johnny Depp is definitely an underrated actor. Sure he does roles that are a bit crazy but he has done roles that are not so crazy but still damn good. He isn't afraid to be different, weird, strange, loving, drag, a bastard, drug addict and so on. He does what he feels is right to him and doesn't always try to be mainstream.
People should see The Libertine, Sleepy Hollow, Blow, Man who Cried and Fear and Loathing Las Vegas. Great examples of his work.He is more than just a good Edward Scissorhands or Captain Jack Sparrow.