Sheila, obviously. I have always been a huge fan. And I think the party could use an injection of the kind of spine she and her fellow rat-packers provided back in the day. Bob Rae is a fine orator and a good leader (interim or otherwise), but running an effective opposition means finding ways of getting under the government's skin. And I'm not seeing that yet (although the walk-out was a good stunt).
And yes I realize the party Prez doesn't have much to do with the day to day performances in the HOC.