For me the first game to blow my mind was the first resident evil.  Everything about it was "cool", then the next game that got me back into gaming was metal gear solid 1 and then 2.  This caused me to purchase a ps2 just to experience those two games.  And had not gamed since the nes era as a little kid until those three games pulled me back in

Easily Zelda: Ocarina of Time. My first game for the N64, and practically my first 3D game in general. I bought it not even knowing what Zelda was, but because I liked the sword and sheild cover. Bear in mind I was 8.

Imagine my surprise. Just try. Before that the best game I'd ever played was Doom.

Super Mario Bros. 3.

I could fly, I could turn into a statue or a frog, I could use warp whistles, I could go to a Giant Land or a Pipe Land, I could ride airships with cannons and flamethrowers everywhere, I could play minigames against my friend, and I COULD KILL THE SUN.

And I could rock this: