Boy, I'm glad I make mostly lap quilts. Three and a half to four yards of 42" fabric almost aways works for me. I, too, believe that the backing is an important part of the quilt, and I look very carefully for just the right one. Luckily, I have an SR Harris store a half hour away that sells all of their fabrics for $6-$7 a yard. There are some cheaper fabrics there, but they have many Andover, Marcus Brothers, etc., fabrics too. It's a huge warehouse store with thousands of bolts of quilting cotton and any other fabric you could imagine from canvas and upholstery fabric to the finest silks. I love to go there and just wander the aisles.