I'll join in on this battle war.
Naruto vs. Orochimaru- Well, since Sasuke used the Cursed Seal which was given to him by Orochimaru to win, and slowly corrupts his brain at the same time, I don't see how this isn't fair.
Naruto vs. Sasuke-This fight was fair for the most part. I think the ending might have been different had Naruto not decided to hit Sasuke's forehead and Sasuke decided not to hit Naruto's stomach
Sasuke vs. Orochimaru- if Naruto get's the Kyuubi, Sasuke gets the CS. It's fair in this aspect, seeing as they weren't that far off from each other. Orochimaru was in a body that was rejecting him even farther, and even Sasuke stated that the only reason he won was because Orochimaru was weak.
Sasuke vs. Deidara- Very fair, unless you count the fact that Suigetsu was able to summon Manda at the end. It would have been a draw anyway. I'd say it was fair because Sasuke had enough foresight to prepare everything before he went up against Deidara, who caught him off guard.
Naruto vs. Pain-Yes, Naruto had prior knowledge, but keep in mind that Pain was dumb enough to raid Konoha like a stampede of elephants, fight everyone because he thought he could take everyone out (which he pretty much did), then fought Naruto. VERY low intelligence on Pain's part, but then again, Hinata also triggered Naruto's Kyuubi transformation. In a fight by themselves in the middle of nowhere? Pain would likely have defeated Naruto, unless Naruto decided to go Hachibi and have Yondaime stop him, which wouldn't happen.
Sasuke vs. Killer Bee- Whoever said Sasuke "underestimated" Killer Bee is ****ing retarded. Underestimating your opponents in manga nearly ALWAYS leads to an asswhooping. He is going up against the second strongest tailed beast. Yes, he was aiming only to capture, but Killer Bee was beating on Sasuke so bad it wouldn't have mattered, and it appears that Killer Bee did not intend to kill Sasuke either because then he couldn't leave Kumogakure for a "vacation", plus all that compassion shit that makes a brotha vomit.
Sasuke vs. Danzo-Danzo did not have access to his right eye for most of the fight, had Karin figuring out his abilities, and had to conserve chakra in case Madara decided to fight. This was one of the most unfair fights Sasuke had (but a good one nonetheless). He could have put Sasuke in Shisui's ninjutsu, or at least used the Body Flicker technique instead of Izanagi.
Naruto vs. Kakuzu-this battle went in Naruto's favor. I agree.
Sasuke vs. Itachi has been discussed in detail many, many, MANY times. We know that Itachi set it up. Nuff said.