I AM A FAN OF SASUKE! AND PAY ATTENTION TO WHAT THEY SAY IN THE SHOW AND YOUR FEEBLE MIND WOULD UNDERSTAND!
You're such a fanboy!
Itachi may have been surprised that Sasuke killed Orochimaru, but Orochimaru knew he was no where close to actually killing Itachi, and that he would die instantly if he challenged him. That was the only reason why he was going to take Sasuke's body because with the sharingan he would have actually had a chance. So just because Sasuke can kill Orochimaru doesn't mean anything about him vs Itachi.
And also read up on your manga, kid, Sasuke isn't the strongest character by a long shot.
Pay attention to what was said in the manga. Naruto got strong just like Sasuke did. Kakashi himself said that with the wind rasen-shruiken that Naruto is more stronger than Kakashi and Naruto would have killed Orochimaru if he had gotten a 5th tail. Naruto would demolish Sasuke especially with his kyuubi seal wearing off, meaning he gets into his tailed-form more faster and in more tails.
Had to make me go me type this long post. But anything to bash Sasuke.