From SFO to AMS, I like to get a right side window seat taking off from 28r so I can take pictures of San Francisco as it Banks to the right. However a left side seat is nice when taking the polar route because you get a good look at the Northern lights, also known as the dancing curtain, so it's a bit of a trade-off. On the return from AMS, I like the right side so I can see the North Pole as it were. Also the sun is not in my eyes from the southern view of the left side of the plane.