I would say Saving Private Ryan (1998) is at the top of the list for me in this genre. I love the intense and realistic portrayal of the D-Day landings, even through I know the director took a lot of liberties with that sequence. 

I also love how they go about on the mission to rescue Private Ryan. 

I know war movies are not supposed to be emotional, but this one caught me due to the brutality of the war and the numerous sacrifices made by soldiers.