New York City has long possessed beaux arts grandes dames and pioneering modernist towers. But for many years, while the Middle and Far East were building like crazy, it was quieter on the Big Apple front. Not so today. If one thing has become crystal-clear during the current boom, developers have come around to the value of good design. Developers are now turning to top local firms as well as superstars from abroad for buildings that are making singular contributions to the skyline.