What exactly do you want to see? This city has the world to offer...
Most above covered the normal spots that one must see. (although the entrepid is @ west side hwy., not west st.)
I can provide you with some tips on how not to be a potential target:
Know your subway route. Understand that a Brooklyn bound train running through Manhattan N/S is running south. The trains are not well labled and to the untrained ear, the loudspeaker is unintelligable. "Spresss stops, this train makin spresss stops" means that you are on the express train.
People in NYC are friendly, we have no problem giving directions, but "excuse me?" will not often deter us from continuing on our path. If you need help finding something, just ask (without the excuse me, or sir, etc.) "Hey, Where can I find (whatever)?". This is not because people in NY are assholes, we have too many bums, homeless, scam artists, etc.
I see many tourists that often respond to the homeless/beggar crowds (because they had a cool sign, etc.
) Please DO NOT give these people money.
Again, there is a lot to see, I would be happy to help, let me know what you are looking for in NY.