Shape-shifting is typically my answer to this question.
It's a power I've wanted for a long time, I think...once I realized that I have crappy self-esteem and just generally do not like my appearance at all. I could look like anyone or anything! One day, I could be a kid, and relive preschool. The next, I could turn into a bird and soar the skies. Then, the next day, I'd be some gorgeous super model. Then...I dunno, turn into a cat and sleep all day. OR, I could make things up, like turn into a centaur, or a mermaid, or a moogle. This would also come with certain regenerative properties...Like if I lost an arm I could just shapeshift into me, with both arms. I guess that means it would come with some limited form of immortality.