Healing powers, for sure! The world could use more compassion and the ability to heal would allow me to make a real difference in people's lives. From physical wounds to emotional scars, I'd be there to mend them all.
Sometimes I want to be invisible. But if we talk about useful superpowers, super health and / or so that the body can not be overloaded (even without sleep). Too many hours of sleep per day, and so much could be done)