Locally, Quilter's Destination in Arlington Heights, IL (fantastic batiks)
For a road trip, The Quilt Shop at the Essenhaus in Middlebury, IN (charming, with many samples, decent selection of metallics) and Lolly's in Shipshewanna, IN. I have not been to Hancock's of Paducah in person, but Lolly's was the biggest non-warehouse store I have ever seen. Over 15,000 bolts, all the known designers/manufacturers I could think of to look for. If that is not enough, the lower level of the same building has two more extension stores, one totally full with nothing but sale fabric, and another with nothing but minky (not sure of spelling) in every color/texture that can be had.
The Cutting Edge, Antigo, WI (incredible selection of reproduction fabrics)