I don't know if you would actually call it my "favorite" kill or not, but I think that the most memorable "sort of kill" of the entire series was Buffy stabbing Angel at the end of Season 2. I say that purely in appreciation of the scene, the actors, and the way that it was performed, with no Spuffy feelings whatsoever involved. I've always been a sucker for the "I could not love you near so much, loved I not honor more" type scene. The struggle, the pain that Sarah portrayed, plus the shock and confusion. Not exactly betrayal, but at that moment there was a "How could you?" look on his face (apparently during his century in hell, he came to understand her actions and accept the fact that he, or at least Angelus, had screwed up, and he had to pay for it) The first time that I saw that scene, ol' cynical, hard hearted me actually got a little choked up.
And then Angel had to ruin the whole thing for me by finally revealing in "The Girl In Question" that he not only knew what had been coming, but he actually MADE Buffy do it by signaling her with his eyes. Talk about let down!
