Either World of Warcraft or Legend of Zelda: Ocarina of Time.
In Warcraft... I remember the first time i stepped into the Barrens.. Yes it's become an absolute buttend of all WoW jokes, but it is still one of the most awe-inspiringly beautiful vistas in the game. Ashenvale had the same effect on me. The music combined with the visuals were just incredible.
Ocarina of Time just... Yeah..Gorgeous game.
"Wing Commander III: Heart of the Tiger" is pretty epic, too, just considering how dark and dreary everything was. It just seemed like things were constantly going wrong, and so when you finally have a chance to end the War....It was epic.