http://www.amazon.com/Bose-SoundDock-Portable-Digital-System/dp/B000V2FJASI've heard quite a few different portable systems, seems like everyone in the family has a different setup. While there are obvious trade offs to any portable mp3 setup, the vast majority have abysmal sound quality.
The B&W Zeppelin is the best small form mp3 player I have heard, but isn't truly portable. The product above is very crisp on the voices and treble, and plays at a decent volume for an extended period of time. It's the only Bose product I would recommend, and is very overpriced. I think you can still demo it at Best Buy.