Greetings from Soggy Seattle!
For a long time I wasn't too fussy about what I used for backs, mostly I used sheets because there really wasn't much extra wide fabric back then except for muslin. Then I started planning the backs as part of my fabric selection. I do love the extra wide backs out now, some are gorgeous pieces of fabric in their own right. I mostly work in scrap quilts and I've started using multiple fabrics for the back as well, if I'm going to have to piece it why not make it obvious?? I have access to a long arm machine and it hasn't been a problem to have a few extra seams.