Old iPods Still Rock

A guy I know just sold the iPod he got from freeiPods (referral points to me) on eBay. That got me thinking- since this freeiPod phenomenon became so popular, there have probably been a lot of people selling these things on eBay for really cheap. Upon checking, 4Gs (the 20GB model available through freeiPods) are going for nearly full price: ~$285 (lists at $299)
But the older models?
15GB 3G, which came out less than six months ago: ~$100 (factory sealed)

And used 3G, 2G, and 1G models can be found for even less.

For a great history of iPod models through 3G, check out iPodlounge's 'Instant Expert: A Brief History of iPod'. And then for 3G vs 4G, check out iPodlounge's Apple 4G iPod: Power Users' Review