I would totally recommend the Rockerfeller Centre over the Empire State Building, having been up both. The Rockerfeller Centre is slightly smaller but way better positioned and laid out and the view is just out of this world, Central Park directly beneath you, just amazing. Glass screens instead of awful metal mesh stuff.
Thanks again for all the new suggestions too. I am getting very excited. I'll definitely check internet for vouchers, and I like the idea of the ferry. (I am not sure if the Statue of Liberty is still closed due to storm damage? but will check it out.)
I second Ellens Stardust Diner, really good fun! Also look for Dylans Candy Store, a real life Willy Wonka store, amazing!
Our DDs loved the carousel in Central Park, a cruise around Manhatten and we loved The Oyster bar in Grand Central Station. Rockerfellar Centre was really good fun too, in fact we prefered it to the Empire State building and as another poster has pointed out you get the Empire State in the background!
I love the Met in NY - your DDs are about the right age to enjoy it. Its right in central park - lovely to wander around, can ride bikes around it or have a horse drawn carriage ride around it. Central park zoo is fun - small and easy to wander round and the polar bears are great.
You can get the ferry over to Statten Island and check out the statue of liberty.
Underground really easy to navigate over there.
My kids loved the Warcraft carrier museum - lots of planes on there and great interactive area - but they are younger and boys. Its down by the pier area - rather touristy but nice to wander through.
Also I wouldn't bother checking voicemails- just tell people to text then you can get the info but don't have to reply. Do any of you have an iPad/iPhone/iPod touch thing that you could take and connect to wifi. I did this then used Skype to give parents a call.
Travelling- kids will probably be fascinated by the entertainment system so that should buy you some time on the plane. Plus mealtimes take some time. Depending on which airline some have games etc on the screens.
If the children aren't used to flying something to chew/suck on as you take off. Helps when/if your ears pop.
We tried to avoid the subway etc during the rush hours. Tried to be somewhere by 4pm and then walk from there so didn't use subway again until after 7pm.
If there's anything in particular you'd like to know just ask.
We quite enjoyed the Rockefeller Centre as you can walk around more freely and get the Empire State in the poto shots!
Would also recommend that a day or so before you go you search the Internet for shops you hope to shop in with "shop + coupon" you can get some really good vouchers. Also worth signing up to their mailing list - Hollister, Aeropostale all quite good.
How about the 9/11 memorial? Free but you do have to book tickets in advance.
Any travel tips welcome too. We are not seasoned travellers. Have been lent a phone for use in the states. Do people just divert their regular mobiles to voicemail and pick up messages? It looks expensive to receive calls.
I think your DDs are just the right age to enjoy Ellen's Starlight Diner, just off Times Square/Broadway. It's a 1950s style diner, and all the waiters and waitresses are actors waiting to get into Broadway shows. They sign songs from the shows and dance as they serve the food, and it is great fun. The food is what it is - burgers, milkshakes, fries, onion rings etc - and is perfect examples of what it is.
And they do updates of how former staff are getting on "Hey guys, you remember Katie who worked she - she got Mr McClaverty in Cats..." Lots if whooping and cheering.
Going for a week with family (DP and DDs 9 and 14) We've got a guide book and have planned galleries, The Hi Line, Central Park, Empire State Building, general sightseeing and some shopping, but would love to hear other suggestions.