Hello All, I'm looking at getting a refurb and was wondering if anyone can tell me what the difference between: 1.) Refurbished iMac 24-inch 2.8GHz Intel Core 2 Duo and 2.) Refurbished iMac 24-inch 2.8GHz Intel Core 2 Extreme http://store.apple.com/1-800-MY-APP...ertifiedMac&wosid=4EZRNLLZkVq123kgV0q8eP2xMxJ They are both priced at $1649 which I find confusing since the first system has a 320gb HD and the other one has a 500gb HD. Are the Duo processors better than the Extreme? Which one is the better system and deal? Thanks!