Okay before you chew me out, I like to bring something up. I heard a few people mention that the only reason why Sasuke beat Orochimaru, was because he was in his weakened state. But if Orochimaru was in his top form, would it had made much a difference? I know you guys probably don't understand what I'm saying, but on all accords, Itachi has never laid a finger on Orochimaru, yet Itachi is given so much credit for taking him down, when he merely used his sharingan. Suppose Orochimaru is the better shinobi, he is one of the great Sannin, but Sasuke stated that him wanting the Uchiha power made him ridiculous or something.
Perhaps Sasuke was right, if Orochimaru was not so obsessed with the Uchiha's power, he could have been better off and would not have been defeated by Itachi. If Itachi and Orochimaru squared off without Orochimaru attempting to steal Itachi's body, do you think the outcome could have been a little different? Orochimaru tried to take over Itachi's body, but his sharingan's genjutsu was stronger than Orochimaru's, so if he just went out, with the intent to kill, don't you think the battle would have been longer and more thought out on Orochimaru's part? Than we have Sasuke telling Karin that Orochimaru was in a weakened state when fighting him.
If Sasuke's anywhere near Itachi's level, that could mean a numerous of things. Perhaps if Orochimaru was not so obsessed, he might not of underestimated either Itachi and Sasuke's sharingan, and believed that their bloodline traits was the only source of achieving great power in the end, he could have learned to avoid the Sharingan's genjutsu and fight with them on a better level. We've seen Deidara break down Sasuke's sharingan's genjutsu, perhaps Orochimaru, with his skill in genjutsu, could have had a better chance against Itachi...