We haven't seen enough of Itachi to really form an opinion about him.

If Oro still had his arms, I would say him.

And to tell the truth, we really haven't seen too much from Jiraya in a real fight either.

My guess is that it would be a toss up between Jiraiya and Itachi. Hopefully we'll see more from them soon so people don't have to keep relying on their manga knowledge.



As for Gaara, at that point in the series, he was reallly impressive. But after seeing the sannin fight, I don't think he's the strongest. Gamabunta gave him a run for his money. Imagine what Jiraiya and Gama could have done. Or Tsunade with Katsuyu helping. Heck, Manda alone against Gaara would have been a treat to watch.