What would be some nice, soothing (and distracting!) music to listen to while in labor?

I’m 27 weeks pregnant, and the time is coming where I should start preparing to give birth. dammit
Last time, I was quite unprepared to deal with the pain other than screaming for pain meds. I had a long labor (24 hours) so I’m hoping this one is at least a little less. I labored at home with my first for a little over 14 hours, and was too focused on the pain.

This time, I’m getting a birthing ball (basically a giant ball that I’ll bounce on…hoping gravity helps), and listening to an iPod to tune out the rest of the world.

What sort of music would you recommend?

I do not want anything too upbeat, probably no rap, nothing pop-rock.
I’m thinking things like Snow Patrol, Coldplay, Sia….that sort of thing. But, since it’ll be hours..I’ll need some good suggestions!