One of the most interesting versions of this to me (though the show itself wasn't always interesting) was Xena: Warrior Princess, mainly because here was an example of a character introduced as a villain (in Hercules), then given an entire show devoted to the idea of her struggles with/against "redemption". Intermittently, there'd be people who showed up who remembered her from her villain days--people who hated her, loved her, were created by her--and we'd have flashbacks to her villain days (giving us a chance to see her fierce, free and unrehabilitated). What I liked best about Xena when they were working her right is that none of her villainous qualities ever really went away--she was still nasty, wry, prone to want to solve things by force and/or charm, more than occasionally driven by her crotch, etc. But she retained a vague sense that there were other ways to live, and emulated them mainly because she had someone else right next to her (Gabrielle) to whom living like that came naturally, which it never did for her.