There are a bunch of great places to go (window) shopping if you like:
The Apple Store on Fifth Avenue is actually quite fascinating. (5th and 59th)
Also, FAO Schwartz is right next door. (5th and 59th)
Also in the area are Barnes and Noble (and Borders, which is closing soon. – 59th and Park)
Build-a-Bear is also in the city. (Near B&N)
I’m sure there’s a Toys-R-Us in the area as well. (No clue where.)