I agree.
My example is KotOR. Graphics are pretty bad by today's standards, but the soundtrack has some very powerful themes that never cease to evoke emotion in me. KotOR II is much the same. I associate specific emotions with the various themes, and those themes make both games so much more enjoyable. (For example, the Ahto City theme. On my first playthrough I visited Manaan last, and so this was after Bastila had been kidnapped. I always feel sad when I hear this, but I love the theme to death because it reminds me of just how incredible it was to play through the game the first time... and many times after that.)
Journey is another excellent example of how music can add to a game. It would not be anywhere near as good were it not for the music. Warhawk has fantastic music, but it was sadly rarely used because the game was online only. I'd end up sitting on the menu screen just to hear the whole song play. inFamous has a few particularly powerful themes that made their respective scenes much more intense. (Genesis, The Truth, Pleasant Empire.)
