At this point, probably buy an apartment in Brooklyn or Harlem, maybe Queens. Or maybe a house in Brooklyn/Queens.
Pay off my parent's house, and if they wanted another, I'd buy it for them. I'm not sure I'd give them money straight up, though. Maybe some kind of retirement fund for them.
Pay my tuition (I'd no longer qualify for financial aid, and I'd pay back any scholarship money I got so someone else could have the same opportunities) as well as my brother's grad school tuition and my best friend's student loans.
ANDDDDD, I'm at around $545 million and I'm running out of things. I'd buy myself a newer/safer car, but nothing outrageously expensive. I'd probably buy a couple of my friends new cars, too.
Eventually, after I finished school, I'd most likely end up buying some kind of commercial real estate to turn into a music venue/nightclub, and maybe open another dog rescue similar to the one I volunteer at now - a small scale, house style property set up with runs that houses rescue dogs.
Oh, I'd redo my ex boss's store. Maybe buy the property for her, if the owner was willing to sell, or get her another location, and renovate it.
I'd also eventually want to buy a house away from the city, and maybe more smaller vacation homes.