I love that there's a museum dedicated to American art, founded at a time when American artists were underappreciated. The exhibitions are curated with a broad but discerning eye, and the architecture is spectacular. In my experience it's typically much quieter than the obvious choices like the Met and the MoMA - although both are remarkable, there's something I love about the scale and style of the Whitney.
Within an couple hours' drive of NYC, you can find lots of sleepy seaside towns. Not only can you get your soft ice cream and salt water taffy on, but you can still spot cool, hand-lettered signs and other relics of a past generation's amusements.