Minato, because he was already Hokage.
The position is more than just being extremely powerful, it also takes a leader with the right mentality to be Hokage. All of the people listed have a version of the Will of Fire (i.e. protecting one's comrades), but both Itachi and Nagato had messed up philosophies. In other words, Itachi and Nagato were willing to sacrifice the free will of the people that they were protecting in order to maintain peace, and thus, I wouldn't choose either of them to be Hokage.
Jiraiya, Minato and Kakashi were all nominated at some point to be Hokage, and they would all make good Hokages.