Kristy, Gerry's right!
NYC has SO much going on in December. You can make a whole vacation out of just looking at the lights and window dressings in the store windows! Not to mention the shopping!!!
The tree, Rockerfeller Center, the Rockettes!! Perhaps a David Letterman or Conan show...
And they have regular commuter flights between the cities, so you can probably get some really good airfare!!
One problem, though... LOTS of Yankee fans!