Sasuke seems pretty weak, he was almost not able to defeat Deidara.
Naruto is just not the strongest, when he uses kuuyibi's maximum power, he wouldn't be alive anymore.
Jiraiya is the best sannin at this moment, but I doubt he is stronger than the first hokage.
Tobi wasn't able to beat the first hokage, but I bet he trained very much I bet. So I think Tobi is the strongest person. Pein is also pretty strong, but I think he has that power not from his own and only use summon techniques.