Per the subject, I am looking for a 6-8 TB External Hard Drive - preferably USB 3 connection. I currently have two 4TB external drives - one upstairs and one downstairs - that I use on my two main systems and "backup" by keeping them in sync. Because I do a LOT of photography (among other things), I am coming in on having only 1 TB free on each. I figure by this fall at the earliest, and next spring at the latest, I am going to have to replace these. I'd prefer to go 8TB so that I can again have at least two years growth, but haven't seen anything bigger than 6TB in the little amount of looking I've done so far. I'm inclined NOT to look at NAS for this because working with large image and video files over a primarily wireless network is less than desirable. On the other hand, I am willing to be convinced
I see what you're getting at here. Currently, the largest commonly available disk size is 4tb. With that being said, the best value/gb would be a 5400rpm 3tb drive. If you have a desktop, thats not an aio, you can add the drive itself into your computer and run the computer through SATA in a raid configuration. This will be more effective than what it looks like you've setup here, as you can access that computer directly over your network and transfer files, or use a variety of mediums to transfer the files instead.
If you have a laptop, or really need an external hard drive, theres an equation for the effectiveness of a buy e=b/$. Effectiveness is equal to benefit to amount spent.
Hope this helps.