So I got a Synology Disk Station (model DS110j) since my wife wanted a server. I figured that the NAS was a good way to go, and Synology is well reviewed. One of the features of the diskstation is ...

If you're looking for superduper easy, you can turn on SSH in Sharing which automatically enables its built-in SFTP server, but you don't get much in the way of added functionality from that.