I listen to a lot. don't use my iPod for music much at all.
Our OC library also has a big list for download, more and more that work on iPod (if not, burn to CD then rip back to mp3).
I also have a membership to audible.com for downloads
I listen to a lot of adventure books and a lot of historical nonfiction - and some bestseller type murder cops stuff
These I recommend (a short list off the top of my head)
Crazy for the Storm by Norman Ollestad(sp?) 11 yr old survives plane crash
Into thin Air
Last Voyage of Columbus by Martin Dugard (plugging for a guy I used to coach) and Knockdown
other books about Everest climbing and ocean wrecks & races like Hobart - can't remember titles right now and my company blocks audible to look at my list