Best Halo game out of the trilogy!
I don't want to kill the ending but I will tell you this: remember at the end of every Halo game-they always show you a cutscene after the credits so you might want to stay and watch the full credits. Even though Half-Life 2's story mode mops the floor with Halo 3's (no offense Bungie), it's still a really great game. I think this game is worth every penny, even when you finish story mode, you'll find yourself playing it again.