Oh, dear. Y'know, I'm in the belief that every game in the series after VII sucked, and there are a LOT of protagonists in the series that I hate. However, I did quite enjoy IV and VI...
Favorite: Locke. I think his story is fascinating; he displays a chivalrous, unafraid treasure hunter attitude, when on the inside, he's quite insecure and is struggling in various ways - the world is in some ways counting on him, he must choose between his wife and Celes, he feels responsible for his wife's "death". The depth of his character isn't really exposed too much in the game, but it doesn't take much thought to realize.
Least favorite: Tidus. He was literally always, always whining. He has this perception that the whole saving of the world revolves around him, but in reality, he's not that important. I just hated everything about him, and also about X.
Let the hate mail come in.