Growing up in Minnesota our summer vacation would always be to New York, Shelter Island or Maine, so the East Coast is very near and dear to my heart. We would actually drive for days to get there and would stay with family.
New York is a faced paced, high energy melting pot with every culture represented in the cuisine that is on every block of the city. My favorite thing to do is take the train to different neighborhoods and just explore. There are unique shops, events, broadway, art and events happening everywhere and everytime you visit will be more unpredictable than the last.
If you visit during the summer vs during New Years Eve you will have an entirely different experience. Whenever you go, you will no doubt fall in love with the Big Apple.