It may not be my favorite public space in Manhattan, but it's way up there. Grand Central has turned 100 years old. It has its own website: http://www.grandcentralterminal.com/ There were multiple articles in the New York Times about it.
There was also a very cool "10 Things You Didn't Know" piece in Time Out New York by Nadia Chaudhury. My personal favorite trivia bit is that Track 34 (because unlike the other tracks, it doesn't have columns) was the location of Fred Astare's dance up the ramp in The Bandwagon.