Call of Duty
The game has many great set pieces that make you really feel like a war hero, fighting alongside your allies and comrades... parachuting into D-Day, holding a bridge from a large siege, storming into Stalingrad with nothing but a few bullets in your hand. It does get a little silly sometimes, especially in the British campaign, when you clear out and take down a heavily fortified dam singlehandedly, race to an air base, and hold off several bomber planes with a single turret.
It's a very fun, exciting shooter, enhanced by the presentation which is strong even now, although I wish more time was spent fighting alongisde large groups rather than by yourself or with a few others.