So many awesome battles but Naruto Vs Pain was epic!
My fave part of that one was when Naruto takes out God realm Pain and yells out to him "Why don't you give up on trying to stop me?". Or even the bit at the end when Pain revives all the people he killed since he invaded Konoha after Naruto decides against killing him to honor Jiraiya and what he taught Naruto. That part I found very moving.