We flew to New York via LA on Virgin Australia, they were excellent to travel with and with a direct flight you can't complain. We then flew Delta from LA to New York, I would never do that again. Hopeless. But we got there in one piece and our luggage arrived too so I guess we can't complain too much.
In New York we stayed at the Langham Place Fifth Avenue, which I would highly recommend. On Fifth Avenue, one block away from the Empire State Building, it was in an excellent location and the staff and hotel services were top notch. There was also a Michelin-starred restaurant in the hotel - Ai Fiori - which was brilliant and also served breakfast!
Of course we went shopping on Fifth Avenue, walked up to Central Park, visited the Museum of Natural History, ate dinner at Picholine (I highly recommend this restaurant), had brunch at Friend of a Farmer in Gramercy Park (which is where I want to live if I ever move to NYC), went on a helicopter flight around the city (AWESOME), went to both decks of the Empire State Building, visited the Intrepid Museum, saw Grand Central Station (how all stations should look, in my opinion), ate cupcakes from Magnolia Bakery, and generally had an awesome time.
We caught a train to Boston, which was a great way to see the countryside without the trauma of driving on the wrong side of the road. In Boston we stayed at the Fairmont Battery Wharf, which was really nice. After our drive around the New England region, we came back to Boston for a couple of days. Visited Little Italy, Harvard, MIT, did a tour around the city, ate at some nice places, the names of which I don't remember now, and generally had a lovely time.
We flew with Virgin America back to LA, they were excellent. MUCH better than Delta. The Virgin lounge in LAX leaves a lot to be desired, but hey it's a place to sit while you wait for your flight. Then we had a very pleasant overnight flight with Virgin Australia back to Melbourne. I would definitely fly with them again.
Oh, and we did a flight over the Lake District of New Hampshire in this bi-plane, which I would highly recommend if you ever get the chance.