Of the Wikepedia list, I liked 47 of the war movies listed--for various reasons.

Ones i'd choose, not just for realism, but for stories and because of the actors involved (and this is tough to choose)

As THE best war film of all-time and you can't get much more real than this film--as well as everything you see used in the film is authentic--including the destroyed German cities:
#1) Decision Before Dawn w/ Richard Basehart, Oskar Werner, Gary Merrill and Hans-Christian Blech.

The rest are not necessarily in order but:

Cross of Iron w/ James Coburn, Klaus Lowitsch, James Mason, Maximilian Schell and David Werner.

Thirty Seconds Over Tokyo w/ Van Johnson, Don DeFore and Spencer Tracy.

Hell To Eternity w/ Jeffrey Hunter, David Janssen, John Larch, Sessue Hayakawa, George Shibata and Goerge Takai (Mr. Sulu of Star Trek fame). This is the story of Marine Guy Gabaldon, who btw, is still alive and living on Okinawa. Guy Gabaldon is known as The Pied Piper of Saipan. This movie has the most realistic Banzai Charge/Bayonet fighting I have ever seen in any movie.

The Longest Day w/ the Duke, Robert Mitchum, Richard Burton, Hans-Christian Blech, Gert Frobe, Curt Jurgens, Robert Ryan and so many others.

Dunkirk w/ Sir John Mills. Has actual footage in it shot by both the Germans and the Allies.

Colditz w/ Sir John Mills and Eric Portman. True to form story of allies officers escaping the Colditz Schloss Prison Camp.

The Password Is Courage w/ Dirk Bogarde. Great allied prisoner of war escape movie.

Hell Is For Heroes w/ Steve McQueen, Fess Parker, James Coburn and Harry Guardino.

Pork Chop Hill w/ Gregory Peck, Harry Guardino, George Peppard, Bob Steele, George Shibata, Norman Fell, MArtin Landau, Gavin McCloud, Woody Strode and Robert Blake.

Too many great war movies to list and this should be a top 100 list instead.

Some honorable mentions:

A Time To Love and A Time To Die w/ John Gavin, Erich-Maria Remarque, Lisalotte Pulver, Don Defore, Keenan Wynn, Jock Mahoney and a very young "Dana" Jim Hutton.

The Train w/ Burt Lancaster, Paul Scofield and Wolfgang Priess.

Sink the Bismarck w/ Kenneth More.

Back to Bataan w/ the Duke and Anthony Quinn.

Merrills Marauders w/ Jeff Chandler, Claude Akins, and Ty Hardin.

The Great Escape (need I say more?)

Kelly's Heroes w/ Eastwood and Savalas.

Where Eagles Dare with Eastwood and Burton.

The Dirty Dozen w/ Lee Marvin and Charles Bronson.

Stalingrad w/ Thomas Kretschmann.

Die Brucke.

08/15 trilogy.

Just to name a few.

__________________
Lost are only those, who abandon themselves) Hans-Ulrich Rudel.