There's Himawari Kunogi from XXXHolic. Aside from fortunetellers, Shinto priests, and other magically powerful figures, everyone who comes into contact with her is cursed with terrible misfortune. For instance, her teacher was found having an affair soon after she joined his class, and his wife stabbed him in the face. Her bad luck has been responsible for a number of accidents, suicides, and questionable deaths.

Himawari is upbeat in spite of her condition. She uses a smiling, cheerful facade to keep others at a distance so that she won't hurt them. Yet she can't shut herself up alone in a tower. When the boy who has a crush on her falls out of a second-story window because of her curse, she makes a deal with the Witch of Dimensions to bear his scars for him. And much angst is had by all!

... wow, is Himawari really the only female angsty scar contender that's come up? That's kind of sad. I guess angsty scars aren't considered to be as sexy on girls as they are on boys.