I sometimes forget to turn my music on when writing. But not often.
I use the music as a sort of "auditory cocoon" to surround me. It shields me from external distractions and helps me focus on the writing.
That's why it needs to be familiar music. If it's new music, then the music is a distraction.
On Dvorak keyboards: I've sometimes been tempted to experiment with the "other" keyboard layout. But I never have. On the other hand, my typing isn't the slow part of my writing.
-David