I think they'll get to be more of collectables after the following have happened:
1. G3s stop showing up in surplus lots. Right now, schools are still unloading them.
2. The generation born between 1982-1997 start to get nostalgic.
As far as which ones will be worth something, I think you'll see the greatest demand for the original Rev. A Bondis, the Flower Power and Blue Dalmatian 2001 models, and the Sage model (which was only available for a few months). I see the G4 iMac being a hot item someday too, but not the G5 and later, mostly because the designs are, in a sense, quite boring.
1. G3s stop showing up in surplus lots. Right now, schools are still unloading them.
2. The generation born between 1982-1997 start to get nostalgic.
As far as which ones will be worth something, I think you'll see the greatest demand for the original Rev. A Bondis, the Flower Power and Blue Dalmatian 2001 models, and the Sage model (which was only available for a few months). I see the G4 iMac being a hot item someday too, but not the G5 and later, mostly because the designs are, in a sense, quite boring.