LMAO!!!! xd + rep
@OP: Legendary Weapons + Superior Intellect and Attitude. Itachi wins
EDIT - If Itachi wanted to kill Sasuke at their big fight it would have been done. The fact is, he did not wish to, he instead wanted to 1) get Oro out of him and 2) transfer his abilities before he died.
Now if we instead had EMS Sasuke vs MS Itachi at that time, MAYBE Sasuke wins. But it's still doubtful as his Susanoo isn't as well equipped. Sasuke's Susanoo doesn't have legendary weapons, just "normal" susanoo weapons. (Still good, but not as good)
But lets say that EMS Sasuke DOES defeat Sick, Dying Itachi. Is that really that great of an accomplishment?!