It depends on how supernatural it can be. If I stay away from the "magical powers that make me able to do absolutely anything" type choices, I would say I'd like to be super intelligent with the ability to read at an amazing speed, read peoples expressions, learn new skills instantly and those types of things.
I would be able to teleport or the floo powder or whatever it is called on Harry Potter would work. I just would like to be able to travel like that. Spend an afternoon in Paris and then go visit my parents in Iowa for dinner.
Marusia- I love yours! I tell my dog that in my heaven he can talk to me. I hope that is true.
I would either want to heal like Claire in Heroes, or be a werewolf like Elena in Kelley Armstrong's Women of the Otherworld series (and have the entire set of superpowers that come with that!)
I would like to have Jedi mind powers: be able to influence people, read minds, have telekinesis, be able to predict the future, and have super speed. But I would also like to have Superman's powers. He is awesome.