Most likely the $599, as they already stated that they will be phasing out the 60GB, which they probably already stopped manufacturing.
I'm just guessing that Sony sells the 60GB PS3s to stores for about $449, which then get sold to consumers for $499. Thus, if they lose $200 selling it for $449, the manufacturing cost must be around $649.
The cost to upgrade the hard drive to 80GB will be miniscule, and since they are switching to 65nm, they will probably end up losing only a very little amount once the new SKU gets released.
So Sony will be selling the 80GB PS3s with the smaller processer chips for $549 to the stores, and $599 to consumers. The cost for them to make these will probably be around $600 at the time the SKU gets released.
This is just all my speculation.
