I ski by myself way too often to not listen to music..have a selection of songs that get me going. I've noticed I push myself more and go a little faster out of my comfort zone if I'm listening to music. Otherwise I'm too careful.
Unless its a day of very difficult conditions, then I usually leave my MP3 player in the bag so I don't kill myself..
*~It is better to go skiing and think of God, than go to church and think of sport.~* -Fridtjof Nansen