[Cardboard]

Mine would be telekinesis, specifically the ability to move anything, of any size, with my mind. Because then you could control every atom and subatomic particle in the universe. You can create clones of yourself, make yourself virtually indestructible, and even if you are damaged, you can put yourself back together again. (Also let's you make food out of thin air ;) ). Also means that if you're strong enough you can move yourself at superspeed too.
Or am I just cheating by picking this power? :P