Claudia Black really impresses me as an actress. I never could have envisioned her playing anyone other than Aeryn Sun, and then I saw her as Vala in SG-1 and blown away by how different the characters were.
Its funny, I can't imagine her playing anyone else other than Vala, but it will be interesting to see her in Farscape when I get to it. I've liked the stuff I've seen with her. Plus, she's also a great voice actress, Morrigan was my favorite character in Dragon Age Origins, and without Black's voice acting, it wouldn't have been the same. Same with Chloe in Uncharted 2. She was also good as Cheetah in the Justice League: Doom animated movie. She hasn't done a lot of very popular stuff (on wikipedia she doesn't have seemed to have done much that I've seen outside of stargate, although her being in an episode of Xena is kind of funny, I can't imagine watching a Xena episode and just randomly seeing Claudia Black show up) , but whenever I see she's in something, I'm excited.