Everyone has their own playstyle. Some prefer to have the Minecraft soundtrack play in the background while mining and fending off monsters at night, and others, myself included, don't really. Disabling the music slider is an option, but if you're playing mods, all that music is gone as well.
This resource pack is a super light-weight way to turn off all vanilla Minecraft music without the slider or by using silent sound files. It tells Minecraft to use empty sound registers for all music calls, and that's it. Heck, the largest thing is the icon.
