My inner sense tells me that I'd have to go with Kakashi... just because I don't think we've seen the extent of his skills yet. I mean, there's got to be more to him than just Sharingan and Lightning Edge. Let's not forget he become a Chuunin at the age of 6 and is a complete genius. Also in the Hospital room, he admitted himself that he wasn't in shape to battle the likes of Kabuto. But once he gets warmed up... it's going to be interesting... I hope