In Book 2, there're two moments that trigger songs in my head, always:
1. In the Farrock caves, that intermittent sound of distant, echoing wind conjures up the song Wind and Snow, by Grouper. If you haven't heard this band, their songs kind of sound like they're drifting into your mind sort of gently and surreptitiously in your sleep. Beautiful stuff. Well... listen and you'll see (or hear, rather) what I mean.
2. Every time I hear the music on the level-up screen I'm reminded of this song by Black Heart Procession. Specifically, the end-of-verse phrase, heard first at 1:26 on this particular clip.
I don't know, I thought maybe someone would find this interesting. It's better, of course, that I'm reminded of music I like rather than music I hate.