FFXII by a distance for me. Even at Distant Worlds it's lucky if it gets anything played. Not having Uematsu in charge seemed to put hardcore Uematsu fans (which are most FF fans) off, which is unfair to Sakimoto. The music was awesome and atmospheric the whole way through, and worked perfectly for each locale of which there were many. If I were to listen to any OST without actually looking at or playing the game, it'd probably be FFXII as it holds up nicely as something to just listen to while doing pretty much anything. I've often used it as an alternative soundtrack to games in which I could mute the base music (or the game didn't have base music), for example Minecraft.