Grew up right outside the city. Damn, its hard to try and fit it to one day. Definitely check out the world trade center spot/memorial, super gripping and really puts things into perspective. Take a walk through Times Square, grab some pizza, theres a pretty cool elevator ride you can take to the top of the Empire State Building for like 10 bucks I think. Wax museum is pretty cool too. Will you be there for that night too? If so, the nightlife is a whole different story.