Rikku is my favourite female, though I prefer her in X-2 for some reason. For my favourite male, it's probably Tidus.
Auron is right up there, but the fact that for the first part of the game, when you're fighting by his side, all I was thinking about was, "aww... that's so cool! He doesn't have the use of his left arm and he's still 5 x better than I am..." But then later on, in Luca, he all of a sudden can use that arm and continues to do so in battle. I'm... very confused. He made me feel sorry for him for nothing. So my friend and I make fun of him. XD