Mine would definitely have to be Twilight Princess. Aside from being too easy, I love everything about this game, from the music, to the dungeons (and their fantastic boss fights), to the art style, to the extremely memorable characters (especially Midna, who is my absolute favorite video game character). It may not be the most innovative title of the series, but it's certainly one of the few Zelda games that I can play through again and again without ever getting tired of it. Twilight Princess is not only my favorite Zelda game, but also my favorite video game - period - of all time.
