I was surprised to know they are still selling the classic iMac. I'm pretty sure they're just using up the stock now.
Has it occurred to anyone else that the classic iMac might even be a bit, well, collectible now? The first iMac was judged a "design icon of the twentieth century" along with the coke bottle and VW beetle. Perhaps in a decade they'll actually be worth more than they are now!
If I see an old iMac going very cheap, I'd pick it up even if it is a little dated, simply for that reason.