For me, it would have to be Rothbart, from Richard Rich's 'The Swan Princess'. He's just so awesome. For one, he's a smart villain...sorta. Tries to take what he wants legally (for the most part), learns from his mistakes, and he's got an awesome voice actor. (Voice actor is Jack Palance, and his singing voice is by Lex de Azevedo).
No more mister nice guy, no sir-ee~
No more mister nice guy, no sir-ee~