Since we're straying from "spaghetti" into westerns in general, my vote for the best westerns of all time are relatively current:

For serious western: The Unforgiven
Clint Eastwood at his best both behind and in front of the camera.

For fun western: Silverado
Every cliche' played with tongue-in-cheek seriousness.

For hilarious western: Blazing Saddles
The genius of Mel