1) Hiruzen vs Orochimaru-as other user stated it's supposed to be how ninja fights should go:elemental attacks skills and strategy,not just sheer power.
2)Neji vs Kidomaru-kind of random but we saw some strategy in it.
3)Sasuke vs Naruto-well that was epic,simply put,a well played mix of taijutsu and ninjutsu,and some little haxx in the middle.
4)Sakura & Chyio vs Sasori-damn,this was so epic,just remember the puppet work that Sasori and Chyio were displaying,the craziness of the fight.
5)Deidara vs Sasuke-well this was an excellent example of what is called versatility in battle,displayed by Sasuke,just the sword play sasuke used to gain enough momentum to hit Deidara,IMO that was brilliant and well written.
6)Itachi vs Sasuke-this battle is all time classic material,the showdown of the Uchia brothers was just godly epic,the speech Itachi gave about reality,the shuriken exchange,the Kirin,the Susano'o.It was just too epic.
7)Naruto vs Pain-the epicness going on in this fight,was just to much for me to bear all at once,i had to take breaks in between the panels.
8)Jiraya vs Pain-same as above
9)Sasuke vs Danzou-man if Sasuke had haters for his awesomeness,with this fight the list just enlarged by tenfold.As he kicked so much as* that it was even painful for the readers.
10)Itachi's resurrection and the sealing of nagato.
PS:i didn't include the fights of the 4th shinobi world war as most of them have being off paneled or still in progress.