Give a man a fish and feed him for a day....Teach him to use the internet and he won't bother you for weeks!
Although these globes are the only piece of subway art I can really recall seeing (because there's nothing ELSE to look at when you're on the escalator), this Subway Art Guide offers up a virtual tour of the public art found in the NYC public transit system. Unfortunately, most people probably rush right past most of them.
~Liz