Galleries? Bonni Benrubi, Throckmorton, SoHo Gallery, Hous Projects, ICP, MoMA, The Metropolitan Museum to name a couple. As for areas to photograph, well... it would be easier to define where NOT to take pictures than places of interest. The entire city is extremely photogenic. I'm sure you will be spending much of your time in Manhattan, which is all fine and good - tons of stuff to see and do there. But don't skip going to other parts of the city. I recently started venturing out into Brooklyn on my trips up there and there is so much to see there as well. Definitely take the subway across and get off to wander around DUMBO (which stands for Down Under the Manhattan Bridge Overpass) - there are all kinds of neat restaurants and shops in the area, and historic buildings too, plus it gives you a chance to see the Manhattan skyline. You can also walk across the Brooklyn Bridge, an iconic structure and a bucket-list item for many people. If you're with your whole family, take the subway all the way out to Coney Island to walk the boardwalk, have a hot dog and fries at Nathan's, and ride the rides at Luna Park.