Zelda: Ocarina for me (I imagine it's gotten a few mentions on here already). First game I played as a kid that really captivated me. It blew my mind how big and rich the world, the story and the characters were. Recently dug out a bunch of old game stuff, my N64 included and I'm, amazed by how much I'm enjoying it again. Although to be fair, there's a heavy nostalgia factor there.
