We really, really enjoyed the Grey Line open air evening bus tour. We hopped on about 8:30pm in early July and saw all the sights of the city as darkness fell and the lights came up. They take you over to Brooklyn so you can look back at the nighttime skyline of Manhattan- fabulous! I see you have a daytime bus tour booked already so this would probably be overkill/ redundant, but we really enjoyed it. The only caveat I have about the daytime bus tour is to be prepared to spend much of your time sitting in city traffic
Try "Becco" for dinner. It's affordable (by NYC standards) Italian food; owned by Lidia Bastanich (sp?) who you might know from TV. The food was fabulous, the wine super-affordable (<$25 a bottle), and the atmosphere casual (although we were glad DH was in dockers/collar shirt and I wore capris/nicer blouse). It's between 9th Ave and maybe W. 45th St? Something like that, check their website.
I would NOT go to Serendipity for supper! High prices, mediocre food, of the omelet and sandwiches variety. The frozen hot chocolate was... good, but really it was more of a frozen icy chocolate drink, kinda like a frappucino from Starbucks (but all chocolate). We felt it was a huge waste of our time and money.
Also try Brooklyn Cafe (between W56th? 57th? and 7th ave- check website). Amazingly well-prepared comfort food, although a little pricey. They do great renditions and generous portions of things like brisket, mac and cheese, pot roast, etc. If I remember correctly, we spent maybe $75 on dinner for 3.
Statue Cruises are the only ones that are allowed to dock at the Statue of Liberty and Ellis Island- everything else is a float-by- but we really, really liked Ellis Island. The immigration story is amazing, and there are many artifacts, documents, etc. We wish we hadn't been so tired and it wasn't so late in the afternoon, or we would have investigated this further. It's on our list for next time, even though the Statue of Liberty isn't!
We really liked MOMA and the Met. I am not an art fan- just don't know anything about it- so I was amazed at how much I enjoyed MOMA. At the Met, there is WAY more than art! Think of entire halls filled with suits of armor, medieval arms, etc. Room after room decorated in different periods from history (like authentic French Provincial), an entire Egyptian tomb. REally, really cool stuff!
If you ever were a Beatles fan, stop by Strawberry Fields on the western edge of Central Park (maybe around 71st ST? check a map). This is a tribute to John Lennon, funded by his wife Yoko Ono (she still lives in the Dakota, across the street, I believe). It's very peaceful there and a beautiful place- and all the tourists seem to catch the spirit of peace and harmony... "Imagine!"
Radio City Music Hall tour is cool, Madison Sq Garden tour also is very interesting and cool to be in the arena, in a box, right down to (but not on) that famous floor. I LOVED the NBC studios tour. (gee, maybe you should skip the day bus tour... do some of the "behind the scenes" tours and take the evening bus tour for the overall view of the city!). Walking around Times Square is a tour all by itself! I also really enjoyed going to the Empire State building.. but didn't go all the way to the top as I didn't want to pay for it, just went to the upper viewing deck! Didn't get to top of the Rock, but wanted to.
OK, enough! I was in NYC for 10 days and still have things I want to go see! Anything you do will be amazing. OH, hey, if DH is an airplane/WWII etc, buff, there is a great exhibit on board the USS Intrepid, which is perma-docked on the Hudson, at the end of 10th? Ave (once again, working from memory, but you can check it all online). You board the battleship and all these really cool planes are parked on the deck. You can also wander around inside the ship, up and down and in and out!