I often go to fabric stores when I travel and have to say the best is right here in Madison. They have a wide selection of fabric from fancy silks to everyday cottons.
You can find something to make a wedding dress from to fabrics for home decorating projects. The owner is very informed about what fabrics are best of a project. I wanted to make some curtains from a silk fabric and she warned me that silk would not hold up to much sunlight. She helped me find a fabric that would be light and airy like I wanted. I ended up with a loosely woven linen that lets in filtered light , but does not look heavy.