The ReadyNas Pro is a good solution for storage, no doubt. A stand alone server, can provide more capability (domain controller, e-mail server, etc) than a NAS. It is really a matter of what you want and how much you want to spend.
If it were me, until I was sure what I wanted to do, I would download and install FreeNAS on a PC with lots of disk space and use it in the interim until a solution is determined. This would cost you nothing and would provide the storage solution desired (at least in the short term).