NYC & Co better update their marketing materials, because New York City has a new name...The Big Onion. At least that's what Stephon Marbury is calling New York these days. While professing his love of yesterday's NY Post cover (we can't argue with him), Marbury e-mailed The Post, "I must say the front page of The Post has to be the funniest thing I have ever seen in a long time. I'm sitting on......