Apple announced late last year [1] that they had seen some battery problems with the original 2005 iPod Nano, and that if you sent it in you'd get a replacement. There was some speculation as to whether you'd get back a refurb or "new old stock", but it was widely reported that what you didn't get was a new iPod. But replacing batteries in those models is a pain (you have to de-solder and re-solder the connector), so it made sense on the face of it for anyone with one that still worked to get it replaced.
Ours had gone missing, but turned up last week while looking for something else. I applied to Apple for a return authorisation, received in the post a couple of days later a pre-paid envelope and packaging, sent the iPod off (having wiped it), and waited for the replacement. Which turned up this morning: a brand new 8GB iPod Nano.
As it happens, I'm not entirely overjoyed: I like click-wheels, and 2005-vintage iPods are the best things to connect to the 2005-vintage interface in the car (firewire charging). But if you happen to have an elderly, but still working, iPod Nano, it might be worth getting it replaced to see what toy you get in exchange.
[[ Update: in fact, with the very mysterious Griffin adaptor which allows Firewire accessories to charge USB iPods, my ancient ICElink in fact does drive the Nano. It doesn't drive Touches and iPhones properly because it doesn't know how to get them into iPod mode, and if you put it into iPod mode by hand it tends to come out when you plug in the accessory. ]]
ian