Probably Midna. The other sidekicks were good and all, but didn't have as much involvement as Midna did. Those that did have that much involvement really just didn't appeal to me that much. Navi was just your little helper throughout the game and annoying for the most part. Tatl was the same as Navi except less annoying with more of a personality. Ezlo was pretty good and above the previous two, but not the best. The King of Red Lions was awesome, he had a huge part in the game as your boat and I think that was pretty cool. He didn't have too much of a personality though. I suppose he somewhat had one, but not much of one... Phantom Zelda really didn't appeal to me all that much. She had a bigger part in the game, but I just didn't like the idea of her. Ciela was stupid, I didn't even notice she was there throughout 3/4 or more of the game.