Whether you started with a 2600 and a joystick in your hand, an N64 with a blistered palm or building your first PC in your teens, what is that one video game you've played at some point that to this day sits at the top of your list.
Final Fantasy 6 for me. The bad (mad) guy TRULY winning was just the coolest as a kid. It definitely tore apart my expectations for what a good game was ever since.