Of course it depends on what you like. Broadway shows are always a treat and there are half price ticket booths in Times Square and at the Seaport in lower Manhattan. You don't get the latest shows that are still in high demand, but there are many great shows available at dramatic reductions in price.
There are all sorts of wonderful museums, depending on your interests. (science, all sorts of art, transpotaion, natural history, etc.) Don't forget the 9/11 center. It's a bit of a downer, but worth seeing. Also, of course, the Statue of Liberty!
If the weather us nice Coney Island, in Brooklyn. Wonderful restaurants, all over the city, of almost every type abound. Little Italy has lots of great Italian spots, and Chinatown is one of the best places for Chinese food in the US. Pizza, in New York, is spectacular. My favorite is Johns (with four locations) but there are others that many people argue for as their favorites.
Just walking the streets of the city is amazing. I could go on for days, but I'm out of time!
Yes NYC is amazing alright. There are sooooooo many wonderful spots to eat and drink, make sure to get out and mingle with the locals as no matter what others say we always find New York natives to be some of the most friendly and helpful folks around. Just get out and enjoy everything you are able and maybe even take the ferry boat ride one evening around Manhattan.