Cheap 2TB HDD for under 100$, cheaper than those two 500GBs you have set aside for over 100$. (If you are going for size)
http://www.newegg.com/Product/Produc...82E16822148413
If you are going for a good RPM:SIZE ratio I say go for these, 1.5TB with 7200 RPM. Both are the same price, your call
http://www.newegg.com/Product/Produc...82E16822148337
If you plan on heavily overclocking and don't want to be bottlenecked by your read:write speeds on a standard hard drive, I suggest you invest in a SSD, and use it only for boot and high end games, and have a secondary drive for
data storage