Atmospheric, Immersive AND Dynamite Soundtracks.

[Koh]

Or AIDS for short.  Heh.

These are the soundtracks that look beyond trying to get the player to headbang or foot tap, though they get bonus points if they do.  These are the OSTs whose primary focus is to not only set the stage for what's happening around the characters in the game world, but also to invoke all the proper emotions of said scenes onto the player as they play, fully enveloping them into the world.  What examples can you bring to the table?

I'm going to cheat and bring two of the highest tier examples into the fray.

Final Fantasy Tactics (sample)
Needless to say, this game's OST is a masterpiece.  Every single track does their job of fully immersing the player in what's going on, as well as evoking all the proper emotions during their needed times.  If I could wish for anything with this OST, is for some tracks to be used more than the one or two times they're seen throughout the entire game, because they're that good.

Vagrant Story (sample)
By the same composer as Final Fantasy Tactics, the OST here once again does the same perfect job of setting the atmosphere and mood.  My only real complaint here is that there's no music during most of the gameplay, save for boss fights and cutscenes, just like Tomb Raider.  One could argue it makes it more suspenseful this way, but as Final Fantasy Tactics has shown, you can make proper tracks to evoke that feeling if necessary.