I have back problems, causing a sharp pain whenever I stand up for a few moments. Considering the fact that my favorite hobby involves getting a good viewpoint on an object for hours, this tends to be a problem for me. I think maybe my superpower would be unnatural amounts of endurance. This would be useful, too, considering the fact that I'm being sent to military school in a few weeks.
Or, instead, the ability to manipulate metal without direct contact. Kinda like Magneto. I've always loved working with metals and wires and such, but I often find myself without tools to use on whatever metals I get my hands on. I would absolutely LOVE to be able to just stare at a pile of scrap in a junkyard, only for it to turn into perfect metal tracks and sprockets for a 1/16 scale Panzer III or KV. Or a nice gearbox. I can tell that would be useful for taking out stripped screws, but I'm not really sure how I would be able to use it for the good of all humanity.