take a look at the Rio Carbon..
the best all-around mp3 player on the market in my opinion. It splits the difference between bulkier juke box players and solid state players. It's a UMS device and will show up as an external drive in pc's and Mac's. Audible compatible, 5 GB's (~4.6 useable), great sound quality (better than my 2g iPod), bookmarking, voice recording, amazing battery life, iTunes compatible, high quality fit and finish and very durable. Not one skip or any damage after 8-9 months of hard use. The form factor is perfect for portable use and about the size of a credit card albeit a little thicker. It will cost a little more than the Shuffle for example but not by much. It can be had for about 170 if you look around.