A while back, I illegally obtained a big zip file that contained all of Douglas Adams’s books in audio form. They’re all read by the author himself, and I’ve been enjoying revisiting them over the past few months (if only to purge myself of the movie version).
I feel no guilt about this, by the way, having purchased all of his books in dead tree format at one time or another, and paid to see the movie.
I’m currently in the middle of So Long and Thanks For All the Fish, and encountered what I think is a hilarious character sketch of a very off-the-wall journalist. I figured I’d share it with you:
My favourite (and Adams’s, as it turns out) is Last Chance to See. I may post an audio bit from that book as well.
DarrenBarefoot.com 
Although more a compilation of smaller works than a work in itself, my favourite thus far has been “The Salmon of Doubt”. I confess I haven’t yet made it to Last Chance to See; but having read the rest of the Hitchhiker and Dirk Gently series, it’s next on my list.
I’d love to hear a bit of Douglas reading from Last Chance to See. It’s a great book. (At the risk of being shameless in my self-promotion, I wrote a bit about the book a while back.)