Definitely window! Like many other people on this board, I enjoy the scenery during flight and especially during takeoff and landing. I actually feel MORE confined when I sit in an aisle seat because all I can see around me is a narrow aluminum tube. Being in a window seat is more liberating (at least psychologically), since you can gaze upon miles of open space instead of the confined cabin. In fact, I go to great lengths to make sure than my window seat is not above the wing. I'd rather sit in the back of the plane than stare at the wing the entire flight.
My flights last about 6 hours on the average, and I usually don't get up to use the facilities more then once. I've never had a problem getting out of the window seat - I usually go to use the lavatory at the same time my seatmate does.