1) Saving Private Ryan
2) Cross of Iron
3) Letters from Iwo Jima
4) Flammen & Citronen
5) Der Untergang
Honourable Mention- John Irvin's "When Trumpets Fade". It was made for HBO, but I think it should have been released theatrically. An good film featuring an amazing Ron Eldard performance.
1) Bridge on the River Kwai
2) Das Boot
3) A Bridge to Far
4) Saving Private Ryan
5) Mr. Roberts
Honorable Mentions: Patton, The Dirt Dozen, Cross Of Iron, Victory, Enemy at the Gates, Von Ryan's Express, 12 O'Clock High, The Great Escape, The Guns of Navarone, The Caine Mutiny, Tora Tora Tora, Midway, The Enemy Below, Letters From Iwo Jima.
The ones I rewatch the most:
Talvisota (aka The Winter War - 1989) - non-stop combat, big battle scenes, largely factual and very involving plot / characterization.
Cross of Iron (1977) - Peckinpah's styling action-editing + Axis focus = winner
The Battle of Neretva (1969) - Yugoslavian film which features some enormous battle sequences and a great international cast
A Bridge Too Far (1977) - Excellent in just about every way except pacing and musical score. Boasts some of the best and most realistic battle sequences seen in a PG-rated war movie.
Stalingrad: Dogs, Do you Want to Live Forever? (1958) - Well-made German war movie from the 1950's feels the most authentic of any East-front German-made film.
Honorable mentions go to: Das Boot, The Unknown Soldier, When the Trumpets Fade, Tora Tora Tora, Bataan (though feels more like a Horror movie than a War movie), The Fought for their Motherland (excellent 1942 Russia battle scenes), Stalingrad, Sahara, Bridge on the River Kwai, The Battle of Britain, The Battle of Okinawa, I Bombed Pearl Harbor (aka Storm over the Pacific), Letters from Iwo Jima, and Windtalkers as a major guilty pleasure (how John Woo handled the battle scenes really reminded my of Cross of Iron).
Avoid: Breakthrough, Codename Emerald, From Hell to Victory,
Top ten:
Where Eagles Dare
Inglourious Basterds
The Bridge on the River Kwai
Fury
Pearl Harbor
The Thin Red Line (1998)
The Dirty Dozen
Kelly's Heroes
The Eagle has Landed
Cross of Iron
Operation Daybreak (1975)
1 Downfall
2 Saving Private Ryyan
3 The Great Escape
4 Where Eagles Dare
5 Cross of Iron
Come and See (1985)
Saving Private Ryan (1998)
Das Boot (1981)
Midway (1976)
The Guns of Navarone (1961)