It depends on the quilt. Baby and kids quilts get minky or flannel. A quilt that will be used for a comfy quilt, as a throw or sofa quilt, usually flannel, maybe minky. For a decorative quilt, I try to use quilter's cotton, something that somewhat coordinates but look for a sale or may have something in my stash. I prefer to have at least a little design on the back since I FMQ on my domestic sewing machine and like the quilting to blend into the back. I don't make show quilts so I don't think I need coordinating fabric from a particular line for backing. I love the look of using leftover blocks, etc. but so far have not been that creative. Maybe one day I will.