I'm a PvE monkey so I've been doing a lot of thinking as what would be able to smash all normal/heroic instances, while I want to keep it simple, I really want to maximize my options, currently I'm thinking of

Pally/Shammy/3xLocks
Pally/Priest/3xLocks
Pally/Shammy/S.Priest/2xLocks

I think the 4 class option would give me the most synergistic toolset, just not sure how difficult they will be the control.