This post will explain how to set up a NAS server with Debian running essential services such as ssh, samba, nfs, cups, rdiff-backup and rtorrent with a web interface; and using two HDDs in RAID 1 mode with everything encrypted. More here
After playing with FreeNAS I ended up using Debian for my server. FreeNAS is a great distribution if you want an out of the box experience, but I found it hard to customise, mostly because I’m not very familiar with BSDs. Also, they are switching to Debian for the next version.