I think I have found my new favorite thing to do in NYC: Top of the Rock (Rockefellar Plaza). It's not as tall as the Empire State Building, but to me, the trade-off of twenty more floors is that you're just less than twenty blocks closer to the middle of Manhattan when you're at Rockefellar Plaza, so you can still see all the way to the George Washington Bridge.
The day we went, it was a beautiful, clear day, and I wouldn't recommend spending the $27/adult to go up if it wasn't that kind of day. But on a day like we had, it was money well-spent to see the views from the top! I'll let you see for yourself.