What I've been thinking for a while is that both die, they are revived with Chiyo's technique, fight it out over who becomes Hokage and then, after Naruto beats (by a slight margin) Sasuke, Naruto gets the spot and Sasuke becomes his right hand man.
i think naruto will become hokage and then naruto will make sasuke hokage and then the story will end. Hashirama said to madara that he was going to make him second hokage but madara refused because he knew that hashirama's brother would have refused to let him become the second hokage. Once the village chooses naruto to become hokage, thats when naruto will make sasuke hokage too and they will both change the village. Just like how the third hokage chose the Minato to be the 4th hokage! Naruto will do the same with sasuke...Then the show will have a happy ending! =D
the other kage will choose naruto to become the Hokage sasuke will mourn itachi raise a family and DOTE on his son(s), one of whom will be called itachi.