This is about my mod called Music Choices, which gives you a lot more choice about what music plays in-game, and where. It will let you play certain music tracks based on things like biomes, dimensions, day/night, creative mode, and also lets you play music in the menu and when fighting bosses, and many other situations!
The instructions for installing/setting up the mod are on the github wiki here: https://github.com/Tmtravlr/MusicChoices/wiki.
If you have any comments or suggestions, or have found any bugs, post them in my minecraft forum thread, as I probably won't check here very often. Also look there for instructions for setting up the music files in 1.6.