Everyone says that the manga says that Itachi says that he and Jiraiya would kill eachother, so he ran away. That means Jiraiya>=Itachi.
That's completely untrue.
Just think a little bit more. What is Itachi's true affiliation? Konoha. What is the the super-powerful Jiraiya a guardian of? Konoha. Itachi would be an idiot if he killed Jiraiya, a guardian of Konoha, so he lied to Kisame about it. Itachi is the 2nd biggest liar of the series.
From what I've seen, Jiraiya has nothing on Itachi. The only thing he can beat Itachi with might be SM, but even then he wouldn't have enough time to enter it.
Amaterasu, Tsukuyomi, Susano'o, Sharingan Genjutsu, etc. From what we've seen, Orochimaru would put up a better fight. And we all know how that went.
Agreed, Jiraiya being above Itachi is one of the biggest misconceptions on this base. The fact that Jiraiya has never shown anything pointing to him being able to counter Amaterasu (except if you expect Jiraiya to casually pick up a scroll and seal the fire while Itachi calmly watches) should be enough proof of that.
Pain is stronger than Itachi, Itachi can't handle all Six at once even with Amaterasu and Deva Path could destroy Susanoos. Jiraya and Itachi may be simply equal. Even though I lean more towards Jiraya being stronger