So in regards to superheroes, some thought.

I've put much thought into the subject, and I think I would have to say teleportation hands down. To be able to be anywhere you wanted at a moments notice! You could see the world, be a master theif, and leave behind awesome smoke effects. Weakness would probably be getting stuck inside of things, splicing, and all that unpleasantness.

Most awesome power with weakness that would suck the most:

Flight, and Gravity.