So you have 2 x 4TB + 2TB + 3TB. Thought about 6 or 8TB drives or is that too much money?
Have you thought about a NAS? Put it in a corner so you don't have to look at it and you can connect it to all the systems in the house. I've got a 20TB FreeNAS server that I can access through all my systems. Living room PC is a tiny dual core pocket PC that just gets used for accessing the server and playing video files.