My choices are all based on having played these games when they were brand-new, as a lot of what makes for an epic scene is seeing stuff that seemed like major advancements in graphics vs. anything you'd seen before.
By this criteria, the game Prey was probably the most chock-full of epic moments vs. any game I'd yet played at the time. Perhaps the best being when you were outside the Sphere flying around inside the glass tube and you could fully see the earth ... most epic scene ever in a game at that point.
Coming out of the sewer in Far Cry and first viewing the island was epic, as was the first hang-glider ride. That game was also the first I'd seen with dynamic shadows, which blew me away at the time.
When you first walked out of the train station in HL2 was an epic moment, as was the conveyor ride inside the citadel.
FEAR also had a lot of epic moments ... one of my favorites being the first time I shot someone with the prototype plasma rifle-thing and reduced them to a smoking skeleton. When Alma was released and promptly wasted her dad was epic too.
Coming out of the sewers in Oblivion ... also a great moment in gaming history.
Trying to get into the NVCP in Stalker before the blowout, when all hell is breaking loose around you and you have no idea how to actually get there ... epic as hell. As is all of lab x-18, and the fight to get to the entrance to the brain scorcher while you're hallucinating all those ghosts and stuff. Not amazing graphics, but they're epic parts of an amazing game.
Going way back, walking into that room with the waterfall in Tomb Raider was a pretty magical moment ... TR was the first time I ever saw a room in a 3d game that didn't just feel like a box. That was an EPIC game when it came out.
I'll also give an honorable mention to a non-game ... the first time I saw real DX9 graphics was the 'Nature' bench in 3dMark03 ... that was probably the single moment that I was the most blown-away I've ever been by computer graphics.
Edited by brettjv - 3/8/11 at 2:05pm