I agree. My preference for characters like Spike (which of course makes me a mysoginist fangirl) is because of the layers, and the story, and the depth, and like you said, the damned darkness. He was the most real character to me of the entire show. I loved Faith, as well. And damnit, I liked Conner. Of course, I liked Buffy, but not to the extent I liked everyone else. Maybe I just saw her through Spike's eyes or something.