This isn't meant as a definitive list or anything, that would be next to impossible, since there are so many brilliant scores written for this genre.
It would just be fun to see some of your choices that comes to mind when thinking of great SW scores.
My list of Morricone, in no particular order:
THE GOOD THE BAD AND THE UGLY
THE BIG GUNDOWN
DUCK YOU SUCKER
THE GREAT SILENCE
ADIOS SABATA (Bruno Nicolai)
MATALO! (Mario Migliardi)
DJANGO KILL...IF YOU LIVE SHOOT! (Ivan Vandor)
JOHNNY HAMLET (Francesco De Masi)
BALLATA PER UN PISTOLERO (Marcello Giombini)