Hope, Vanille, and Sazh in that order.

Sooo... you can take MILF's post as my answer as well, really. xD Hope is just so adorable and makes you want to hug him, and his character development is believable and realistic. He was the most interesting to watch deal with his problems for me. He's also the person I play as in battle, and he's insanely useful with the best summon in my opinion. <3 Vanille is really cute and quirky as well, but then shows that she has her own problems and she's not just simply insane and happy. And Sazh... He's Sazh, so yeah. xD