"She Wore A Yellow Ribbon" - the best of the Ford Cavalary trilogy and proof John Wayne could act.
"A Bridge To Far" - which has everything "The Longest Day" has plus the bonus of being done in colour.
"The Four Feathers" - the original Korda version with Ralph Richardson and C. Aubrey Smith, not any of the three remakes. It benefited from having veterans of the actual campaign serving as technical advisors.
I'll cheat and give honourable mention to "The Lost Patrol".