Raid 5 is data protection on block level there is completely no difference for you on which RAID you are sitting if you looking for backup solution.
If you talking about Personal Documents and not scarred of using cloud data sync folders (like dropbox, google drive or Ubuntu One) I'd say you can put Dropbox onto your workstation and link it with you, lets say Documentsse one of mentioned software folder. And you will have permanent Documents folder that can be mapped to any of your workstations that have access to Internet.
There is description in here
Dropbox Instead of Documents
Or. If you have concerns with Online data storing you can choose one from this list:
Backup software