Good question. I think I would start out as a good guy, but slowly over time, use my powers more and more for evil ... or at least a decidedly brutal good. (i.e. instead of capture bad guy and give them to police, end up breaking their arms/legs/spine so they cannot do evil .. if not out-right killing them). . I'd love to be Superman or a Jedi. But if you are limiting me to a single power. MIND CONTROL!!!!!