I voted for Orochimaru and Kabuto but the truth is I don't know. Orochimaru is strong but who knows if he can even get through the protective puppet. Orochimaru and Kabuto are good with medicine and science but they would need an antidote before hand. Since Orochimaru and Sasori were partners they would know each others techniques. But with the help of Kabuto the sound nin tagteam would come out on top.

The Akatsuki seem to be teamed up like sith, one being the master and the other the apprentice, for example: Pain over Konan, Itachi over Kisame, Sasori over Deidara....
I would have arranged them differently.