Can't decide on one, so here is 5
Zant, I just love his transformation from the coldblooded and controlled evil to the maniac he is in the end
Saria, I don't know why really, but she had some pretty touching scenes
Medli, because the Earth temple is so good, and I love that you can jam with her even if she isn't very good and the little dialogue that appears if you show her the golden feather
Tingle, because he adds lot's of fun, and there is so many haters
Skull Keeta, because his dialogue is pretty moving, tell them the war has ended etc. but all link uses the mask for is commanding the stalkids and tricking Igos