Along the park is the Bryant Park Hotel, my favorite hotel in New York City. Originally built to house the America Radiator Company (the building somewhat resembles a radiator), it was converted to a hotel in 2001. In this view, you can see both the American Radiator Building and the far more famous Empire State Building in the background.
If you visit the park, be sure to download the park's audio walking tour narrated by Matthew Broderick. Its like spending the afternoon with Ferris Beuhler, but maybe not as fun.