It depends on what you want to do. There is so much to do in NYC!
You may want to bring your DS to the Intrepid Sea Air and Space Museum. You can also bring him to the Natural History Museum. Central Park is beautiful in the Fall and, of course, there's the Central Park Zoo and the Tisch Children's Zoo (included in the CP Zoo admission).
There is the South Street Seaport.... Broadway.... Shopping.... Bus Tours.... NYC Movie/TV show location bus tours...... Empire State Building.... Top of the Rock.... Rockefeller Studio Tour.... Madame Tussauds.... King Tut Exhibition......
I could go on and on..... whatever you're looking for, you'll find it in NYC.