I believe the full backup that you do on the weekend of the whole system would indeed restore all of your applications/settings, etc. Most of the settings for the stuff you've mentioned (Samba, mail, ftp) are stored in the /etc directory under the appropriately-named sub-directory. Hardware info and things like your drive layout, etc. would also be stored in various files here. So, after installing your OS some of these files could simply be dumped back into the system for easy recovery, while others would really be used as a reference point I think (like remembering how your drives were laid out). For example, I don't think you could just dump the contents of the /dev file because the system will assign different values to the hardware in a new install, but you could copy the /etc/fstab directory I believe provided you change the UUIDs to match whatever values the new system has given to your drives.