The greatest western ever made.
I know that a lot of people are partial to John Wayne, Gary Cooper, and Sergio Leone. I know that High Plains Drifter, Unforgiven, and The Good, The Bad, and The Ugly are widely considered Eastwood's best cowboy movies. This one is my personal favorite. I think that this one really sums up the West and shows it for what it was. It shows how this anarchic society could turn on anyone in a minute. The outlaws, the vigilantes, and law enforcement were all equally unfair and unforgiving.
I also like Once Upon a Time in the West, The Cowboys, and Pale Rider.