Then ask yourself the question "What would I like for Christmas?"
I've been trying to do that for the last couple of days. My best answer was Your Momma, pictured here (do follow the link; this tiny image does not do her justice), but I have a feeling a true 8-year-old girl would probably disagree.
Therefore, appalled though I am that even an 8-year-old would consider this desirable, I think I'll go with Jacqueline's suggestion of a Bratz Doll (if you value your sense of hearing, turn the volume down before the Flash video starts ... you have been warned!).