ExtremeTech has a great review on Hitachi's new 400GB hard drive here. All in all, it has almost identical performance to existing 250GB drives today with an 8MB cache and a rotational speed of 7200RPM. So, at ~$400 for the thing - you're just paying for more space. My thought: You could get 500GB by buying two 250GB drives today. I've seen them at some retail stores for $139 with rebates. But there would be a certain “cool” factor to it, I agree.