You wake up tomorrow morning feeling a little different. You grab your door handle and crush it, your eyes get hot, and a hole is burned through your door. You step through the hole, travel at superspeed into your kitchen, and suddenly realize you have HIS powers. Forget the reason why, forget about asking how it happened. If YOU were granted the powers of Superman (any age or arc you prefer) what would you do?
I'd definitely go flying around the world, punch some mountains, fly (swim?) to the bottom of the ocean, walk around the Titannic, save some people, and figure out what I'd wear. I wouldn't fly to space right at first, I have a fear of the void.