Option to turn off combat music
http://wiki.guildwars2.com/wiki/Customized_soundtrack
You can replace just the music you don’t want with a silent track or something you prefer from another game. You could also create a combat play list that has say 10 tracks, 9 of them silent and one of them with the current music, which would reduce how often you hear it by 90%.
John Smith: “you should kill monsters, because killing monsters is awesome.”