If you've gone through the trouble of loading books on CD into your mp3 player so you could enjoy Huck Finn on your jog, you might enjoy what might seem to be a step backwards in technology--a dedicated, single-book device. It's the Playaway, an electronic book that our library has bought into.
My first trial was a success, though Bill Bryson's reading of A Short History of Nearly Everything was a little less clear than I'd like. Either that, or the sound quality on the device is a little muddy.
Either way, the device brings books into a simple, stand-alone device. It worked well on my jog, and I look forward to trying it again.