A refurbished 4GB iPod nano will run you $99. A refurbished 4GB SanDisk Sansa e260 will run you $39.99--shipped, no rebates--at Buy.com. End of post!
Well, okay, maybe you need more incentive than a $60 savings. The e260 features a microSD slot for adding more storage, an FM tuner/recorder, a voice recorder, subscription-service compatibility, and a removable battery. The iPod nano features, well, none of those.
CNET lurved the e260, awarding it 4 stars out of 5. I have the virtually identical e280, and apart from its so-so scroll wheel and buttons, it's an excellent media player. Alas, it's not compatible with Amazon's Unbox video service (rats!), so there's no easy way to stock it with movies or TV shows. If you can live with that shortcoming, this is an impossibly good deal.