Depending how fast we're talking probably super speed. I could get to where I wanted by running instead of using flight, and I could do EVERYTHING super fast, hopefully even my metabolism would be increased, and like imagining some thugs starting crap and just being able to deliver tons of punches to them like Kenshiro would be the sickest.
SQ
Yup, superspeed. Even "speed of sound" superspeed. As long as it didn't have stupid requirements like "You have to eat 50,000 Calories a day" or "the friction will catch everything on fire" reality. Just good ol' superspeed with no drawbacks.
I'd definitely use my superspeed to run into a news studio, fart in the Anchor's mouth, and run out before anyone can see it was me. I'd also use it to spank people super super fast. Lessee, what else would I do? I'd definitely move people's stuff when they weren't looking. Drive them crazy.
And I'd fight crime. Definitely.
What other things should I use my superspeed for?