I'd like to start with one of my favorite games, Shadow of Colossus. Great game... even though the controls can be kinda of ass sometimes. But what sets this apart from just being some average game with a unique concept would be the music. This amazing soundtrack makes the battle turn into something... cinematic like. It's pretty damn epic when you get down to it.
Another game that I like, but can't find myself going back to play on a consistent basis like SoC would be Final Fantasy X. An all around good game. What stands above all else when I think about though, would be how great and balanced the soundtrack is. Might be my favorite soundtrack now that I think about it. I knew it was going to be a great game once the blitzball opening began and Otherworld started up.
Never expected to hear anything like that from this series, but it fits perfectly with that movie. Then there's stuff like Seymour's Battle Theme, Challenge, Decisive Battle, and Summoned Beast Battle.
Oh man, then there's the great character themes for Auron and Tidus. Also stuff like This is Your Story, Wandering Flame, People of the North Pole, Assault, The Advancers and many others I can't think of right now. Oh yeah, can't forget the ending theme.
So, what soundtracks have added to a game for you guys? Which ones do you have fond memories of as you played through maybe a mediocre game?