I highly recommend Desperate Quilters. There is a thread here:
http://www.quiltingboard.com/posts/list/17614.page
that discusses their site.
I, too, have shopped at Thousands of Bolts. They label each cut you receive with the name of the fabric, etc. so there will be no confusion. Check the current thread about them on HGTV here:
http://boards.hgtv.com/eve/forums/a/...2/m/4201058893
Fickle Pickle is great, Connecting Threads is great in customer service, as is Fabric Buffet. The only site I would not recommend is Bear Creek Quilting. I'm in the middle of a problem right now, and although it is "resolved," I'm not at all happy with the frustration that I had to endure.