Updated more prices, as usual. You might see some drive prices show up as "=349.99/2", as a formula in a cost cell. This just means that you have to buy 2 drives (combo) to get the drive price listed.
I have added a new column which should be the end to all, in this spreadsheet, for cost per TB per year including electricity cost. This causes some drives that appeared to not be as cost efficient, to possibly edge out ones with higher electricity costs.
You can choose which column you prefer to use, but the option is there to see the "total" cost, as best as I can portray it.
Enjoy!