Since I bought my new iPod (yay 25% employee discount), I've been listening to podcasts. One that's great for longer drives is Escape Pod, a podcast where science fiction short stories are read. I've listened to nine so far, and most of them have been quite good. Sometimes I have to just get over the narrator's rendition of some character voices, but that's probably a standard problem with any audiobook-style work.
The three I didn't particularly care for were "Seventy-Five Years," "Stuck in an Elevator with Mandy Patinkin," and "The Clockwork Atom Bomb." "Seventy Five Years" was essentially two politicians talking reelection politics. Granted, there was an interesting not-in-the-too-far-future "twist" near the end, but that still doesn't make it a story in my mind. The other two weren't so bad, just meh.
But if you only have time for the three good ones, I recommend "Tk'tk'tk," "Shadowboxer," and "Anyone Can Whistle." These ones got me caring about the characters, which is harder to do in a short story than in a full-length novel. They're listed in order of preference, BTW.
Note that you don't need a fancy-dancy iPod to listen to these. The sound files are just MP3s. So go, listen to at least "Tk'tk'tk."