I'd much prefer it if they were *all* off. I don't want to hear a voice yelling out FUROWAH NITEH GIRU if I forget to mute my speakers before re-launching the game after midnight. Same exact deal for the music and sound effects. That's literally the first thing I do every time I log on, kill all the sound.
The only real solution is for the game to save the preference from last time. Otherwise you can't please everyone with one single set of defaults and someone will always be unhappy.