http://www.whittlesfabrics.com/
http://www.shoppersrule.com/ (deals on everything quilty EXCEPT fabric)
http://www.reproductionfabrics.com/ (not necessarily the cheapest, but competitive and beautiful quality)
http://www.connectingthreads.com/Quilting.cfm (because shipping to Canada is $7 for orders over $50. if you order online)