So over the past year, I've gotten into audiobooks big time. The King County Library System has an excellent selection, and you can even download some titles.
What's annoying, however, is that some of the series I've favored have gaps. The first two books of the Kane Chronicles by Rick Riordan are downloadable, but the third isn't (though it IS available on CD). Also, they have the first six books of the Honor Harrington series by David Weber, as well as number 12, but not 7-11 (I'll forgive them #13, as that one is relatively recent). They also have two of the spinoff series, but not the third. And as much as I loved Shadow of Saganami, I'd really love to listen to an audio adaptation of Crown of Slaves, which is hilariously complicated.