Options for small Rapid Recovery 6.* deployment. Server/Storage

Hello,  I am dealing with an aging server hosting Rapid Recovery 6.4.0.718 running Server 2012 and sending backups to a Drobo B1200i over iSCSI.

I am only backing up 5 servers, 2 of which are lightly used file servers. (One of those will be going away soon)

My initial thought was to just buy a decent workstation to host Rapid Recovery Core, and then some type of new storage to send backups to. (our footprint for backups is only about 7 TB)

I currently replicate to a workstation at another physical location across town via a 100 Mb/s fiber connection.

My dilemma right now is choosing some decent, but low cost storage and whether or not it should be direct attached, or also iSCSI. 

Appreciate any thoughts on the matter.