I will only add an alternative to the three HDD backup plan, and that would be a RAID5 array in your main PC and a RAID5 backup system in a NAS drive enclosure. You can relatively inexpensively put together 4TB on the main PC with a 4TB backup in the NAS using six 2TB drives. The RAID5 system allows for a drive failure without losing data on the system. The likelihood of losing two of the three drives at once is very slim, and the likelihood of losing two of the three drives on each of the two machines (main computer and NAS) is almost non-existent. You are probably more likely to be struck by lightning while holding up the winning lottery ticket. Also, the suggestion to use a SSD as your boot drive is excellent. That will make much more difference in the day to day speed of your computer than even a dramatic processor upgrade in most instances.