I've always liked -- even loved -- Morricone scores, but as a general rule, his output has never taken a solid recognizable hold on my music loving awareness like that of other film composers.
The "Man With No Name" trilogy? Pure genius. He created a new world of sound, and I can't imagine those movies without it any more than "Psycho" without Herrmann. But after all of these years, they're the first to come to mind when I think Morricone. At the other end of his output, I loved "The Hateful Eight" but I won't remember a damned note of it until I watch it again. Loved "Cinema Paradiso", "Frantic", and others during the middle years, but I'd have to read through a filmography to jog my memory on a lot of the others.