Real estate has always played a major role in the game of keeping up with the Joneses, but for New York's startup-founding, fashion-influencing, money-making millennials (who, we will remind you, are almost well into their 30s) a white picket fence in Westchester just won't cut it. The new status symbol? A sprawling rooftop, skyline views, insane amenities, and the mailing address of one of these trendy luxury apartment buildings.