I've bought online with good success from the following:
www.fabric.com (free return shipping; they won't say if their products are "first" quality or not)
www.hancocksofpaducah.com (pricey, but a huge selection that you can keep in cart for a long time)
www.hawthornethreads.com (more contemporary and lg scale prints than most; a favorite=color grid)
www.fabricshack.com (they include a free gift)
www.overtherainbow.com (nice emails and service)
I've found quiltshops.com to be very useful for locating specific fabrics from a collection, as I have found oftentimes that no one shop carries all prints or color schemes of a collection.