I have a membership there that lets me download 2 audio books per month, but I never know what to pick.
I prefer fiction, hate romance, hate westerns…
(btw, they have a pretty cool deal–if you sign up for a year you get a free mp3 player that will play your audio books 
I’d post the link that gives me a commission for this but I think I’d get in trubble. Heh. Anyway, it’s a good deal, I got my player about 4 days after signing up!)
I’d go with “The Day of the Jackal” by Frederick Forsyth.
I would have picked Harry Turtledove’s alternate-history novels, but they don’t have any. 
Are you familiar with This American Life? It’s a weekly public radio show that’s addictively entertaining. Each show has a mixture of fiction & non-fiction stories on the same theme. I know you said you were mainly interested in fiction, but this show has such compelling stories that even the true-life stories come across like a well-written story.
I’m not sure if TAL is covered under your 2-free per month deal. But if you aren’t already a regular listener to the radio show, download a couple & give it a try!
I second This American Life. It’s frankly the only reason I own an audible.com-ready device. The show’s just incredible.
actually, specific eps to look out for:
“Christmas and Commerce” - I think that’s the one, anyway. It has incredibly funny stories by David Sedaris (The Santaland Diaries) and David Rakoff (Christmas Freud).
“The Friendly Man” - all segments are by Scott Carrier in this ep. They tend to be of the more sobering type, rather than the lighthearted humor of my other suggestion, but it’s a great ep and Carrier’s book – Running After Antelope – is, right now, my favorite book; this episode contains probably a third to a half of the stories from that book.
If you like political satire, check out Why Not Me? by Al Franken. Very funny. 