I would love to meet anyone from a band/show I like, such as Gwen Stefani, Amy Lee, Brody Dalle, Shirley Manson and Mistress Juliya. I would have no idea what to say to them, but it would still be cool.
I've already met Davey Havok (AFI), Agent M (Tsunami Bomb) & Aimee Echo (The Start) and everyone else in those bands several times, but it will always be a pleasure to meet them again.