Final Fantasy 1, because the music was epic from a seven year old's perspective.
Final Fantasy 3/6, because it was like twenty minutes long, and it changed based on what you did in the game. Given that this was the SNES, that was remarkable.
Fallout, because it blew me away.
And portal 1&2, because the ending songs rock. Not to mention looking up at the moon and thinking "... Well it is white... and moon rocks.... Might as well give it a try even if it is stu OH MY GOD!"