The most fascinating powers don't mean a thing if the guy's poorly motivated or dull, and the most generic powers won't hurt a well-motivated character. Personality and motivation are what make Magneto, Magneto and not Cosmic Boy. The powers work for him, but it's his motivation that makes him the character he is.
I could name you a dozen superheroes whose powers I'd like to have. But if I could have any power in the world, it would be the power to read or watch a creative work and absorb the technical skill of the people who made it. Because then I could have even more fun writing. That's my core identity. I'm a writer. I just love telling stories.