The Name BELOW the Title
Great comments by all on this thread, particularly Lance's insight about what 'stars' are supposed to bring to a film, ie Box Office (better known as the Bottom Line). The Big Name--the Name Above the Title--is supposed to ensure the success of the film at the box office; but I'd like to put in a quick 'vote' for the Name BELOW the Title, ie the supporting actors who often 'make' a film one we really remember for an especially good performance.
Tom Sizemore has already been singled out for consistently excellent roles in 'Ryan', 'Pearl Harbor', etc., and he is a good example of a recent actor whose supporting roles really bring an added dimension to a 'war film.' Someone mentioned Van Johnson's star-billing performance in 'Battleground', yet he had a lot of help from supporting actors like James Whitmore as the tobacco-chewing platoon sergeant and Douglas Fowley who was continually clicking his false teeth. Those of you who remember 'Stalag 17' (starring William Holden) and 'Attack!' (starring Jack Palance) will probably recall that both films were really enhanced by the performance of Robert Strauss, who played essentially the same wise-cracking soldier in each of these movies. An unusual but superb inspiration in supporting casting was in the film 'The Best Years of Our Lives' which starred Fredrich March and Dana Andrews. The role of Homer, the armless Navy veteran, was actually played by Harold Russell, a WWII veteran who had lost both his arms in the war. Although not a professional actor, his supporting role was one of the highlights of this Academy Award winning film.
If we were asked to come up with a list of 'top war film' supporting actors, I think we'd likely list some of the foregoing plus others like Richard Jaekel (Dirty Dozen, et al), Nigel Green (Zulu), Victor McLaglen (John Ford's 'cavalry' movies), Sam Elliott (We Were Soldiers, Gettysburg, et al) and all those great supporting actors whose names you can't remember but whose faces you can't forget.
Band of Brothers is a very interesting corollary of this issue in that by casting 'not-very-well-knowns' in virtually all of the roles, what we got was, essentially, supporting actors who carried the entire series. The 'Star Power' in 'Brothers' was really only the directors, Spielberg and Hanks. As was noted in this forum this brilliant move was one of the key ingredients to its outstanding success.
All of the big names listed at the beginning of this thread have made some excellent 'war' films, and we've probably all enjoyed watching most of them over the years. But I just wanted to raise the issue that when we watch a 'war' film (or any really good movie) it was likely the supporting actors whose performances really made the film stand out.