There is so much to do in NYC. A visitor could do something different every day and night for a year and never repeat themselves.
I love the adventure of the sub way. We decide on a place to go (restaurant or attraction), and part of the adventure is using public transportation to get there. We stay a week at a time so we buy a metro pass. If you haven't been there, the Statue of Liberty is highly recommended. We went to it once, but rode the Staten Island Ferry (free) back and forth twice just to take photos.
We have been there only twice, but want to go back maybe next year. Rockefeller center is neat. Good luck
Jim and Vicky, Belleville, IL
2004 Winnebago Journey
2012 Explorer Toad