Ataraxia and Synethesia
Personally, if I could have a “power” it would be one of these. To live without worry or any preoccupations would be, in my eyes, the closest thing to a truly free life. While I would like not to become preoccupied and worried, it is against my nature. Some might say I am relatively laid back, and I am at times. However, like most people I still have times of stress and worry. To not have these would be an amazing personal feeling. I think there would be drawbacks, but then again you wouldn’t be worrying about it would you?
Synethesia, specifically tone synethesia would be amazing. Every time you hear a musical note, you see color. To see your favorite music while listening to it would be like a visualization you’ve never dreamed of.