ROTS Sidious vs Orbalisk Bane
Now before everybody shouts "SIDIOUS HE'S STATED TO BE THE MOST POWERFUL SITH!!!!!!!" Remember that "most powerful sith" just means that Sidious > Bane, not that Sidious > Bane with ORBALISKS on.
Luke is the most powerful jedi, but that doesn't mean that Luke > an average padawan with the imperial fleet at his command.
So who wins, and please use feats/evidence, not "Sidious is the most poweful sith" because that quote doesn't take the Obalisks into account.
1. Sabers
2. Force
3. All out
And oh, I'm still undecided as to who wins. Haven't read RoT, but I've read PoD.