Personally, I'd have to say Gaara. He went through ordeals similar to that of Naruto, so he understands the importance of love, having to go through without it as a child. He is calm, cool and collected now, making him easy to reason with as well as being a great asset to his nation, who practically only has one very strong ninja in the village to depend on, that being Gaara himself. Watching him grow from from the manga as well as the anime, it really shows how far he has come. From being that monstrous blood-seeking killer, to saving Lee from Kimimaro and slowly opening up his friendship, to then finally becoming a well respected Kazakage of the Village Hidden in the Sand, it gives you that sense of happiness for him after seeing him go through everything he did.
