I would cure cancer and AIDS, then give the world's alcoholics and drug addicts the power to quit. I'd start to make myself hot and rich, but I feel like real God would give me a look and I'd realize the errors of vanity and instead grant myself wisdom or some ****.
Destroy hell
Bring back dead people I miss.
Listen to TPP and R8
Give myself the talent of singing
Make myself hot
Cure the world from diseases
Make a few people die from "natural causes"
An entire 24 hours? All the things i could do in that time. Hell, I could freeze time.
I'd definitely wanted to get to know God on a personal level though. And ask, why are some things the way they are? Do you really have all the answers?