Thought 1 book a month would be stretching it. I took the plunge and now mow through books like crazy. I love audible. I use my credits and keep an eye on daily deals where books are only $0.99 to $3.95. It's especially cool now that it "whispersyncs" with your kindle/ipad/reader. I'll read a little at night before bed. Get up and turn on audible for the commute to work and it picks up right where I left off.
Audible seemed expensive to me, but I think I value it more than cable TV (especially since its not football season). So i think its money very well spent.