I've had three bargello quilt books out from the library: Bargello Quilts by Marge Edie, Bargello Tapestry Quilts by Marilyn Doheny, and Colorwash Bargello Quilts by Beth Ann Williams. It's been a while since I read them, but I think Colorwash Bargello Quilts had the prettiest patterns and the most information. It received great reviews on Amazon.
I hope to make a bargello quilt one day, or at least a wall hanging. I think they're gorgeous!