I don't know if this is really the case, but it always seems faster to me from JFK than from EWR.

SuperShuttle from JFK is $17 a person. There's another bus service that's a little cheaper, but with three people the cab or a car service will be cheaper and faster because it doesn't stop all over the place. If you search in the New York forum you'll find instructions for the cheapest way in - only a few bucks, but it sounds like a pain to me. I just paid $48 including tip for a car service back to the airport from downtown.

There are lots of show discounts this time of year. (Do a search on Seasons of Savings.)Is anyone in the group a student? My son and I brought his student ID and got same-day tickets to Wonderful Town for $25 each. They limit that to two tickets per ID though. Avenue Q also has a daily lottery for cheap tickets.

I like staying downtown, but staying in mid-town does make it convenient for shows. Century 21 is good. I enjoy shopping in the boutiques in Soho as opposed to the department stores that you find in every other major city. If they like hot chocolate sampling, there are a lot of good places to hit for that. You might pass along this website: http://gonyc.about.com/cs/samplesales/
It's filled with all sorts of good things - chocolate suggestions, sample sales, show discounts, etc.