Oh, I also like to use a sheet for the backing. I never have been too fussy about the back because my quilts were hurridly made for kids who were waiting for them. Now that the kids are grown, I can take my time and put some quality into them. Also, I have made every mistake in the book on these quilts. Talk about learning experiences!
It wasn't long ago I saw a picture of a quilt where the backing was as pretty as the top. It was pieced with coordinating colors and looked to me like it was totally reversible. For me, this would be overkill, but that's just me.