World War 2: The Longest Day, Saving Private Ryan, Hacksaw Ridge, Flags of Our Fathers
Vietnam: Platoon, Born on the Fourth of July, Full Metal Jacket, and I'll count Forrest Gump
Grenada: Heartbreak Ridge
Modern Warfare: Black Hawk Down, Jarhead, Lone Survivor, and 13 Hours.
Overall, Black Hawk Down is probably my personal numero uno, with Lone Survivor and 13 Hours my pics in terms of technical achievement (Lone Survivor: Marcus Littrell, the actual eponymous character from Lone Survivor's true-life story, being a consultant, excellent stunt work; 13 Hours: hard-hitting action scenes and the Pearl Harbor bombing shot recreated with a mortar round from Michael Bay)
Just off the top of my head.