My Grandad used to tell a joke about two Cow girls, one wore knickers and the other didn't, known as Raw hide and Shy Anne (Cheyenne, another cowboy series from the 50's)
The Good, The Bad and The Ugly.
The Outlaw Josey Wales.
Unforgiven.
If I had to pick five, the other two Spaghetti westerns are in, if I had to pick a non-Western, Dirty Harry.