My favorite is always the next one.
Seriously, I have purchased a lot of quilting books, and the ones that were the most help when I started are not the ones I look at now. I think we all go through different phases in our quilting, and there are many books that are helpful along the way. I purchased only one Eleanor Burns book, and I was not happy with it at all. Too much about her personal life; maybe not all her books are like that, but it turned me off. I really like Judy Martin's Log Cabin book (and her other books).