All hail the Queen of Blades! Sarah Kerrigan from the Starcraft series (I can type series now, the second one it finally out), is my favorite video game character. Mostly during her characterization in the first game, and its subsequent expansion pack, I automatically hated her, and then realized I loved her character. She was a gung ho strong woman, which during the games initial release 1998, was a legend in itself, but ultimately I liked her because she was a straight up bad guy.
Too many times modern media has tried to give the bad guys frame of reference to provide 'understanding', but Starcraft balanced the fine line of understanding and keeping Kerrigan evil enough to not have the audience be sympathetic towards her. This kept her as a bad guy, and she was unpredictable to boot, especially in Brood War. At one point, after she forces Zeratul to kill his own Matriarch, she boast "I am pretty much the queen bitch of the universe". Sadly, it looks like there is going to be a complete role reversal in Starcraft 2, especially with the open ended ending to the Wings of Liberty Campaign, and Kerrigna is probably going to be at the heart of a tale of redemption, something that I have heard time and time again. Personally, Kerrigan will always be the Queen of Blades in my eyes.