When cartoonist Thomas Nast drew this illustration of future Manhattan for Harper's Weekly in 1881, Trinity Church was the tallest building in New York, with its spire and cross reaching 281 feet into the heavens. Until September of 2001, the North Tower of the World Trade Center stood as the tallest building in the city at 1,368 feet. Today, the Empire State Building is the tallest building in New York at 1,250 feet tall, but with any luck that's likely to change soon(ish).
The much delayed $3.1 billion One World Trade Center (formerly known as the Freedom Tower) will stand on the former site of the World Trade Center as the tallest building in New York at 1,776 feet. It's currently scheduled to be completed by the end of 2013. Let's just say I'm not holding my breath for that date.
Image from the August 27, 1881 Harper's Weekly and the book Predictions: Pictorial Predictions From the Past by John Durant.