This topic seems to be focusing on who is stronger between Itachi and the 3rd. Now don't get me wrong they are both massively powerful but overall the 4th has to be considered number one. He faced the Kyubi(yes I know this is an overused reason). If the 3rd is so great why didn't he fight Kyubi. True he was pretty old at the time but not as old as he was when he fought Orochimaru. Logically he would have been stronger at that time. However, it was the 4th who defeated Kyubi. Even if we assume the 3rd did fight Kyubi, he obviously didn't do sweet fuck all to it.

Also, the 4th was chosen as Hokage by the third presumably because he had become more powerful than the 3rd. He was also chosen over all three of the legendary sannin for the role. That is why Orochimaru left the Leaf. Alot of credit is given to the 3rd for knowing alot of jutsus(maybe all) but the 4th created some of the coolest moves there are such as rasengan and the seal for Kyubi. Also, the 4th's name appears on the frog summoning contract before Jiraiya's, therefore he had another teacher besides Jiraiya which means he must have been taught a wide range of techniques.

I tend to be sceptical about the fight between the 3rd and 1st&2nd hokages. For one Orochimaru resurrected them and controlled them which means that it is highly unlikely that they were as strong as they were when they were alive. And two, the jutsus they used were pretty pathetic looking.

There is no doubt that the third and Itachi are both strong but in the end when the village was on the line it was the 4th who whipped some ass.