I would have to say mine is either a tie between Sanguine and Clavicus Vile. When it comes to gods, the whole 'I am a god. I am mighty. You are weak, and nothing more than a pawn." thing is cool, but it tends to get cliche after a while. My favorite Daedra with this disposition is probably Molag Bal. But I like gods that are a bit different, dare I say, more human. I like gods with a sense of humor. After completing the hilarious 'A Night to Remember' quest for Sam Gueverne, Sanguine has quickly become my favorite Daedra. How about you?