i just pick a folder or an existing playlist and hit random. but the best things for me because they help mask noises (yes, the ones in my head mainly) are musicals (such as annie) or movies with lots of background music (disney movies are good for this) or old-school multi-camera sitcoms for the laugh track (newhart, mary tyler moore, patty duke, etc)… the other common thing between them is it’s all stuff i’ve watched a lot so it’s very familiar. if it isn’t–i’m more apt to try to watch than to doze off.