Sergio Leone was the King of spaghetti Westerns. My three all-time favourite Leone movies are:
1. The Good, The Bad and The Ugly
Hard to go past the great combination of Clint Eastwood, Eli Wallach and Lee Van Cleef. This is the perfect Western.
2. Once Upon a Time in the West
This film is an opus to the Western. Lee Van Cleef is at his absolute meanest and the extreme close ups before gun scenes are to die for.
3. Once Upon a Time in America
Be sure to see the director's cut and not the original release, which was butchered by the studio. Loosely based on the Crimes Incorporated story this movie is challenging (approx 4 hours long) yet ultimately rewarding. Robert De Niro and James Wood are fantastic.