Microsoft probably could afford to sell a 120GB hard-drive for $80/$100 and a 250GB hard-drive for $150/$175 but, with how overpriced their hard-drives have been since day one, I wouldn't expect this from them ...
In my opinion, a 500GB drive is unrealistic because it will (probably) be a $300+ hard-drive for laptops when released, and it would be far too expensive to include in any console at a reasonable price.







