Never turn down a window seat.
Most flights in and out of LaGuardia Airport (LGA) guarantee you some version of a view of the Manhattan skyline, depending on the flight path. You have to guess in advance how to pick your seat. Ideally, you will have a left-hand window seat if you make the approach from the southwest, seeing the harbor and Manhattan out your window. But, if you instead take the roundabout approach where you fly north up the Hudson River and then turn to land from the northwest or northeast, you will want to be on the right-hand side for views of Manhattan out that window. Either way, I highly suggest having your camera handy and your settings figured out in advance.