A very nice, modern observation deck in the tallest building in the country. The views of Lower Manhattan and Brooklyn are fantastic, and the elevator ride, which shows an animation of New York's skyline through the years, is really cool.
It is rather pricey, but that's probably to be expected. I went mid-morning on a weekday, and there was no wait and plenty of room at the top. Fun experience if you can splurge a little.