Of all the engraved items, I have to say I haven't seen one with the Coca-Cola logo before. That's pretty darn neat. As far as tech goes, it's really worth what anyone is willing to pay. What makes it cooler is that it's not something you could have just walked into a store and bought like the HP or the U2 iPods.
To a savvy Apple enthusiast + Coke collector, this thing may be worth $100 or $200 based on function, condition and battery life. To a normal user, this is a $25-$50 iPod because of the form factor which has kept this as one of the best video-playing iPods. That's really just my take. Like I said; find a crazy Coca-Cola collector who's never seen one, and the sky is the limit. (I once sold expired, limited Oreos on Ebay for $100 on a bet.)
Missed opportunity for Coke; not insisting the front was red! haha