Need New Build Advice (First Server Build)

This will be my first server build so I need to make sure I use the right parts and build the best server I can to meet my needs.  The server will be used for Plex and to do local backups for the three computers in the house (wife's laptop, my business laptop and my recently built desktop).  I have been reading this forum and others a lot to try and do the best job I can.  All three of the computers are also backed up to cloud storage.

Obviously I will be using FreeNAS.  I am figuring I...

Need New Build Advice (First Server Build)