Actually, though it may seem laughable to say it
The best fighting scenes I can remember were both from Naruto
The first being Rock Lee vs Gaara and the second Naruto vs Sauske
Only because they're very emotionally charged fights.
With Rock Lee's fight against Gaara it's the underdog against the murderer and unless your a horny fangirl you were rooting for Lee. It something awesome when he just absolutely pummels Gaara and heart wrenching when despite it all he still loses.
With Naruto v Sasuke you can just tell when you watch the episode that they really stepped it up with the animation. I also LOVED how this fight was a lot more physical than others in the series.
They aren't trading jutsu as much as they are trading powerful, angry fists. It's, IMO, the best fight in the series so far with just the impeccable animation and the implications it has. It's not only visually impressive but it's holds great significance to the plot and changes it's tone drastically.
A great way to end the first part.