It really depends on the plane I'm flying in.
Some flights have individual monitors with a selection of movies.
More often than not I wait until after the flight attendants have passed out snacks, drinks, and have come around to collect the waste before I attempt to "relax".
I always bring my iPod along on the flight and recline listening to music while wearing my sunglasses. I tend to drift in and out of sleep. My wife watches movies on her laptop or reads magazines.