If I had to choose 1 I would lean closer to Bane and Zannah, but all of the ones I listed have interesting dynamics, and context to their work, and I enjoy greatly. The great thing about the Sith is the masters almost completely shape the relationship, so you always get unique takes on the duo depending how the master sees and views things. Wish the rule of 2 era was more fleshed out we only see the first generation go, and then the tail end of it, with small bits in the middle. We probably could have a lot more great duos if it was more explored.
I also forgot to list Exar Kun and Ulic Qu-droma, they were another great pair.
