1) Naruto/Sasuke (i'd place Naruto 1st but the manga disagrees and considers them equals).
2) Sasuke/Naruto.
3) Sakura (boss summon, can heal an army, regeneration, overwhelming strenght, evasion, poison, intelligence... too good to be lower).
4) Neji (has the Byakugan and all its perks and is also very skilled with his clans taijutsus; also has a good deal of versatility and fighting prowess that other fighters below don't).
5) Lee (can open six gates, nuff' said).
6) Choji (overwhelming strenght and size, plus works extremely well with Shikamaru and Ino).
7) Sai (well rounded Anbu with a great range of versatility, utility and fighting skills).
8) Shikamaru (not great in a 1v1 but his intelligence makes up for it; great asset to have in a team; great teamwork with Choji and Ino).
9) Shino (seems to be good at strategy and planning, but while he's not a complete one trick pony, he's close; doesn't seem that great in battle either, at least he's not been impressive by shippuden standards).
10) Hinata (weaker version of Neji...; would be higher than Shino if Kishi didn't make her a drawn cliche, he used to and is considered to be strong among his peers, so i gave him the benefit of the doubt).
11) Kiba (great offensive power, hard time putting it to good use; also, too rash for someone who wants and considers himself to be Hokage material, which is hilarious).
12) Ino (great support abilities and excellent teamwork with Shika and Choji, but her apparent inability to fight on her own doesn't let me rank her higher).
13) Tenten (when a higher percentage of a character is filler, there's something wrong; no relevance, last place).