Saving Private Ryan is a brilliant movie, maybe the best war movie ever made, but it's so brutal that it was tough to watch once, and when an old girlfriend wanted me to watch it with her (first time for her, second time for me), I had to look away during the hand-to-hand combat scene where the American soldier is gently but unstoppably stabbed to death. The landing on the beach is also especially hard to sit through more than once.
As for The Thin Red Line, the accents, at least to my ears, make it hard to take seriously, with the philosophising crackers ruminating on the realities and implications of war. Other than that, it was pretty good.
Enemy at the Gates is really good, and based on the true story of the Russian sniper Vasily Zaytsev . I've seen it a number of times. Ed Harris and Jude Law are really good, and Bob Hoskins plays a pretty good Krushchev. Vasily's story here: http://en.wikipedia.org/wiki/Vasily_Zaytsev
Michael Collins was really good, with Liam Neeson in the title role. After Ireland's War of Independence (1919-21), negotiations with the British resulted in the partition of the country into the Irish Free State and Northern Ireland, which remained under British control, and still is today. That was probably the best agreement that could have been obtained at that time, but many in Ireland felt betrayed by the agreement, and started the Irish Civil War (1922-23), a very bitter combat that sometimes had brother fighting brother, as in the American Civil War.
Michael Collins, made in 1996, covers this period, as does The Wind That Shakes the Barley, made in 2006. Both are very good movies.