Brigid Tenenbaum is the best character of BioShock. I don't care what you say. What I love about her is her story. You collect it in audio journals as you run around Rapture, the great underwater city, and it tells about her past in the German prison camps in WWII. Her story arc is awesome. She goes from not caring about anything or anyone but science, as in not caring if anyone dies because as long as you got good data from it, hey science is good. To a mother figure to a large group of little girls she's rescued from being zombie like creatures. It's her fault the girls are like that and she knows it and doesn't try to pretend it's not. She wants to fix her mistakes and that's one of the reasons I love her.
She's intelligent, pretty much discovering and creating plasmids and ADAM by herself at a young age. She doesn't care what people think about her. She's dedicated to her work, before and after her moral change. And when she has it, she is good. She's one of the few people in Rapture that cares about someone other then themselves.
I just wish we could have seen her in the Burial at Sea DLC. It would have been neat to see her stealing away one of the little sisters from a big daddy, because I still can't believe she went around stealing little sisters by herself with no help. She's just too awesome.
I also love her accent and I want to hug her because she needs hugs. I like to picture her with her little group of young girls following after her, trailing her like a mother hen. Mamma Tenenbaum!