Halo: Combat Evolved's climatic, final race against the clock. It was an intense and atmospheric moment, coupled with the fact that everything was getting blown away and that every monster and creature still left alive were running aimlessly as you ran past them trying not to get caught on the explosion. If that wasn't enough, the game tricks you into reaching a specific destination that really takes you nowhere, makes you waste time waiting for something that won't happen and then you have to cover yet another huge distance while the clock is stil going down trying to desperatedly reach your only means of escaping. You leave the car right in front of it and you have to make one final sprint (on-foot) to get to the ship.
Other Halo games (like Halo 3's ending scene) have tried replicating this moment, but nothing will ever manage to be as awesome as how Combat Evolved did it.
