One of the things I like to do when I had a full sound system set up for background music was to create tow different files one for combat music and one for roleplaying or as video games would put it exploration music.
I occasionally would chose a particular song for a particular Npcs. Since moving to texas I don't use music as much as I used to.
These also serve now as background music when I write.
Here are 10 of my current favorites.