'kay, since so many people are asking me my opinion on who is the strongest captain in BLEACH, this is what i think ( based on up to vol.26)
in order:
Zaraki Kenpachi
Sousuke Aizen
Shigekuni Genryusai Yamamoto
Byakuya Kuchiki
Jushiro Ukitake
Shunsui Kyoraku
Toushirou Hitsugaya
Gin Ichimaru/ Sajinn Komamura (tied)
Mayuri Kurotsuchi/ Kaname Tousen/ Soi Fon (tied)
Retsu Unohana