I always say nobody from Earth because then a half dozen would want to be. And 99% of the time their stories and power sets are so convoluted it wouldn't make sense in a six issue comic series. You could be like Superman, technically your homeworld is/was Krypton but Earth is where he lived most of his life. Some of the Legion come to Earth [often looking for a place like the Legion] after they gain powers, others have already lived here for a bit. 

~KL~