Regarding Arby's post, if you wanted to store all those prime numbers on an array of 400gb Hiatchi drives (largest/cheapest available so far), you would need about 1.39277744 × 10^296 drives, at a cost of about $4.31761006 × 10^298 (without shipping and tax, from newegg.com). Of course, they only allow you to order 20 at a time, so you'd have to make 6.96388719 × 10^294 seperate orders.
This is all without cases or IDE controllers, so figure out however many you need.