This subject is so close to my heart. Knitting and Reading are my favorite things, so I am ALWAYS listening to an audio book. I am a member at two county libraries, so I have quite a selection available to me. My favorite audiobooks are either "The Cat Who..." series by Lilian Jackson Braun, or any of the Star Trek tapes with "Scottie" narrating them. It's so relaxing to knit while escaping to one of the imaginary worlds in those books.
My husband and I go to consignment and thrift stores quite a bit, so when I find audiobooks for a good price, I'll nab them. Sometimes, after listening to them, I'll give them to the library.