There are so many threads out there on this topic. I was sewing at my LQS this weekend and we were all debating the pre-wash subject. The LQS owner is an avid pre-washer and she has a washing machine and dryer in the shop which is so handy when you buy the back and binding at a class and want to work on it that day.
I recently got a hand me down front loader washing machine and use the speed cycle to do my pre-washing and I have noticed less raveling with the front loader. When I come home with fabric it goes straight to the laundry pile.