There can scarcely be any better 'showdown scene' theme than "Sixty Seconds to What?" from For a Few Dollars More. Awesome tension-building music and the payoff to a major plot thread in musical form? doesn't get much better than that.
The film The Legend of 1900 is an entire movie about a pianist who lives on a cruise liner. And yet, for all the film's music, the piece that stands out is, although haunting and powerful, the most simple.
Morricone is famous for his spaghetti western scores but he is also famous for others too. Among others: