Its finally done! I've managed to juggle my data around and freed up enough space to move everything onto to NAS.
The only risk at the moment is that all of this is running as JBOD -- meaning no redundancy and no parity. So if one of the disks crashes, goodbye to that part of the data. :-(
Well, the good part is that everything is still extensable. According to the motherboard specs its possible to increase at least four-(4) more SATA disks to complement my PATA drives.
I'll just wait a bit and see if at the end of this month there would be a few other spare drives to be disposed of that I can use.
At the moment the NAS is storing all my collected media for the past decade. With the expanded NAS planned, I'm going to include some work files that I feel uncomfortable storing on my current workstations with a little redundancy hopefully.