Did you know they've been recalled due to battery issues? Well it's true - see here!
Contact Apple and they'll send you a free box to ship it back to them for either a new refurbished version or a brand new battery or a brand new iPod - the jury is still out on what you will receive, but either way, especially if you had battery issues with it, send it back in for a new replacement! The New York Times wrote up a little article about the issue as well...check it out!
This is actually the iPod that I still use; I have the white one. My husband's version in black broke via a battery issue about 2 years ago. We're going through the replacement process which begins here on Apple's Support website.
Here's a quote from the website: "Apple has determined that, in very rare cases, the battery in the iPod nano (1st generation) may overheat and pose a safety risk. Affected iPod nanos were sold between September 2005 and December 2006. This issue has been traced to a single battery supplier that produced batteries with a manufacturing defect. While the possibility of an incident is rare, the likelihood increases as the battery ages. Apple recommends that you stop using your iPod nano (1st gen) and follow the process noted below to order a replacement unit, free of charge. Note: This battery issue is specific to the iPod nano (1st gen) and does not affect any other iPod."