Being a visual learner, I am continually referring to "The Quilter's Ultimate Visual Guide" by Ellen Pahl and any of Eleanor Burns books as they are also well illustrated and written for anyone to understand. For machine quilting and a myriad of other useful quilting info, I rely on Harriet Hargrave's "Heirloom Machine Quilting."
I haven't had the misfortune to find any books that didn't deliver something useful for me.
Great topic!