Definitely Naruto vs. Pain.
Why? Because it is basically the turning point at which Naruto finally became acknowledged by everyone in the village. He singlehandedly risked his life to save every single person, and showed the most effective TNJ (hehehe, love that term) ever to bring Nagato to his senses. Several moments of this "fight" which I loved:
- Naruto's sage mode. Let's face it, Naruto is pretty handsome here, reminds me of a very raw version of Minato.
- Countless surprise faces Pain gives as Naruto keeps outsmarting him
- The fact Naruto is finally outsmarting someone -- it is good to see Naruto developing strategy and not just power. The multi-rasenshuriken technique was freaking awesome.
- When he was able to control the Kyuubi with Minato's help ("Dad!!" D'aww!!)
- When Shikamaru's dad stops the Konoha guys from following Naruto because Shikamaru says "something about him makes people want to follow him", and believe in him
- Just how mature Naruto is during this brief conversation
- The moment after the fight when the entire village welcomes the hero back and Sakura hugs the astounded Naruto; there was definitely something special about that moment.
Yep, pretty darn awesome "fight".
Second best I'd say is Sasuke + Itachi vs. Kabuto, and as you may have guessed, it is not for the fight itself.
