Probably Madara from assumptions, which I agree with.
Pain is probably second strongest.
I have no idea how well Kisame fights, but he was sent by Madara to get the 8-tails alone when Sasuke, Suigetsu, Juugo, and Karin failed. Judging by that and the fact that he has a HUGE chakra supply I'd say he's stronger then we know about. We only saw a 30% clone and his brief scuffle with Kakashi. But no idea about a full powered Kisame.
Itachi would be after Pain from what we've seen.
Uh...Kakuzu next.
Deidara after that.
Sasori or Hidan after that.
No idea about Konan and Zetsu, we havent actually seen either one fight. Unless you count Konans mini battle with Jiraya. I can't really count that. Plus, Konans no longer part of Akatsuki.
Pain is probably second strongest.
I have no idea how well Kisame fights, but he was sent by Madara to get the 8-tails alone when Sasuke, Suigetsu, Juugo, and Karin failed. Judging by that and the fact that he has a HUGE chakra supply I'd say he's stronger then we know about. We only saw a 30% clone and his brief scuffle with Kakashi. But no idea about a full powered Kisame.
Itachi would be after Pain from what we've seen.
Uh...Kakuzu next.
Deidara after that.
Sasori or Hidan after that.
No idea about Konan and Zetsu, we havent actually seen either one fight. Unless you count Konans mini battle with Jiraya. I can't really count that. Plus, Konans no longer part of Akatsuki.