The one problem I have with some of these speaker systems for the iPod is how large they are. If I wanted something that large, I would buy a stereo system. iHome has the iHM1B that is a very portable speaker solution for the first generation Nano.
Comes with a plastic shield and a water resistant carrying case. It also offers SRS™ TruBass for enhanced bass reproduction. While you may not get aboslutely professional sound from something like this, I think it makes up for in portiability what it gives up in sound reproduction.
