I love to use the Quiltshops.com search whenever I'm looking for something. I've ordered from many different stores there. My favorite places are:
Quilt Fabric Closeouts
http://www.quiltfabriccloseouts.com/
Thousands of Bolts
http://www.thousandsofbolts.com/
Over the Rainbow
http://www.overrainbow.com/cgi-bin/Store/store.cgi
Whittles:
http://www.whittlesfabrics.com/cgi-bin/Store/store.cgi
I have found great prices and great service at these places.