I'm personally a big fan of Cid's part because, not only is Cid one of my favorites and only tolerable characters in this game, his part is the Huge Materia quest, which is one of the few moments that I really like and have great fun with. I mean, it's when I can view my favorite scene and whole reason to replay this game after all (well, the chocobos are another reason, but Cid can take care of those too!).

Of course Cloud is the main one but I always keep a save file somewhere of when you can play as Tifa because she is my favorite characters. Plus it lets me have her and Red XIII in the party. (I want Yuffie in the party due to her ranged attacks and healing Limit Breaks)

Literally only one of Yuffie's Limit Break heals, and it's her second one. It heals for half of their max HP.

Well, I do have to admit that having Tifa as the leader is definitely the best time for me personally to go after Limit Breaks, namely for characters like herself, Barret, Cait Sith and Red XIII, that I haven't used around much (legit didn't use Tifa unless she had to be present. Thanks to that, well part of it, I got Barret as my date lol).