Well, I haven't played I-VI yet, so I can't really pick a favorite from there, however, here's my list from the rest:

VII: Cid Highwind (Shut up!! Sit down in those chairs and drink your g--d--- TEA!! )
VIII: Rinoa Heartily
IX: Freya Crescent (because she's a real butt kicker)
X: Rikku
KH: Goofy (the dude uses a shield as a weapon, that's gotta take some serious bawls)

Quote Originally Posted by FinalBob42
X - Wakka (I don't know why there is so much plain out hatred against him.)
Hey, I liked Wakka! I mean, come on, who doesn't like a rastafarian, mon? Besides, he was the best guy to bring in when the enemies liked to attack you from the neighboring continent.....