Michelle Forbes
Knowing Michelle in Galactica, Waking the Dead, The Inside, TNG, Swimming with Sharks, and Confessions of an American Girl...I was realy impressed with her performance. I think she really took the role on well.
She is quoted as saying that she didn't like to play strong and authoritative woman because she wanted variety in her career, but I think the emotion that was required in this role was really a step above anything else that she's done.