Quilting fabric, fleece, minkee, and flannel all work great.
Flannel sheets work ok, too.
I have done enough charity quilts using recycled sheets that we have now banned them. The thread counts are so high, that the needle breaks the threads instead of sliding in between the weave. The quilting leaves little holes allover the back. Even thought they are used for charity quilts, we (the guild that makes them) still like them to look nice.
I have also seen problems with *some* batiks as backs. The weave on *some* is also just like percale sheets- so tight that the threads are broken.
Sewbatik.com has the 108" wide batik backs. This fabric is made for quilters, and is very, very nice! Their flannel is the normal 40" wide, is the most luxurious flannel I've ever felt.
For those of you who need quilting done, I am running a special that involves the SewBatik wide backs. PM me if interested.