Best: 'Donnie Brasco' (1997)
When people refer to Depp as a "good actor," they're usually thinking about Mike Newell's solid gangster saga that proved the star could pull off a serious, brooding performance when he felt like it. Playing real-life undercover FBI agent Joseph D. Pistone (alias Donnie Brasco), Depp spends the movie toggling between 21 Jump Street and Goodfellas modes. Yeah, he spends roughly 82% of his screen-time calling mob confidant Al Pacino a cocksucker (and the other 18% denying that he is a cocksucker, himself), but the man delivers every line of crude gangland vernacular with the barely perceptible anxiety of a guy who's auditioning for the role of his life. Whenever Brasco banters with his Mafia marks or punches an old acquaintance who publicly refers to him by his real name, Depp works to make the character simultaneously authentic and scared shitless. It all builds to one of his best screen moments, when Pistone spells it out to his wife: "I am not becoming like them, Maggie. I am them."