I have a 30MB iPod that after 2 years didn't really hold a charge anymore.  This docking station was a great answer.  I leave my iPod in there and it runs flawlessly.  I did get a nano for the road too... and swap them out when I need to charge it.  There are inserts for different size iPods, but I don't use them, I just swap the iPods and it works fine.

The AC adapter is a bit clunky.