I used to pre wash everything, then I heard people say it was OK not to pre wash. So for a while I did not pre wash. BUT when I started hearing about chemicals etc in the fabrics we are getting (LQS too), I have decided to pre wash everything. I run my fabrics thru a gentle load with out soap and with Shout Color Blocker and then put them in the dryer.
Works for me; however, everyone sees things differently and I respect that. It would be a dull world (and board) if everyone agreed on everything.