I'll second Seattle Fabrics - since its local to Seattle, its a great store to stop in and shop around, their remmant bin is legendary for good finds. There just aren't enough shops around that are worth browsing, that will surprise you with their stuff from time to time - they also have a fantastic supply of cam buckles if that's the kind of stuff you need.
Once again, Thank you Mrs. Barker for teaching me to sew (sorta) in 7th grade Bachelor Survival class...