http://www.gametrailers.com/player/42777.html
The deaths in Gears of War 2 aka Why this game is so awesome.
One of my favorite campaign moments was the sniper sequence while in the caves. Marcus notices the locust far away and says "good sniper practice" or something, so I sniper some. I try to snipe as much locust as possible, pressure gets high and do some perfect active reloads and you feel Marcus get angrier with each kill.
"That's one", "That's two!!", "That's three!!!", "THAT'S FOUR!!", and with each kill I was curious what he'd say next and then the last locust is almost in the cave and I really wanted to snipe him and I just got him by an inch and he says "That's FIVE MOTHERFUCKERS!!". It was such an awesome moment and it felt very natural and in sync with my actions.