Yossi Milo is, in my opinion, the most dynamic and eclectic of the photography galleries in NYC. From portaiture to architecture to experimental digital sculptural giant animals to street photography, they show an endlessly exciting range of work. Some of my favorite recent shows include Simen Johan's mythical beasts, Ezra Stoller's architectural photographs of the TWA terminal, and Sze Tsung Leong's huge cityscapes.
This is a pro tip, but also a summer tip, take the ferry from Lower Manhattan to Rockaway and spent the day. The beach is great and the area is impossible to gasp that it's 30 min from Manhattan (without traffic) - Eat as many tacos you can, cause it's the best in the state of New York!