Building a home streaming server. Need opinions on OS and streaming apps

Hello,

I have a PC lying around with the following specs:

  • Core i5 - 3570
  • 8GB RAM
  • 120 GB SSD
  • Two free SATA slots that I will use for 2x 2TB HDDs

I want to to turn this PC into a home server / NAS but I don’t know what OS to use. I wouldn’t mind installing a linux distro on it, but I already have a Windows Server 2016 and Windows 10 license due to student offers.

Kodi and Plex are also new things to me. I will use it to stream media to my Sony Android TV and my windows PC, which are on the same network. Streaming to my phone would be a nice bonus, but not really mandatory.

Any OS recommendations or personal experience when dabbling with these applications would be very welcome.

FreeNAS 11, freenas has builtin Plex Media Server as plugin, personaly using it, easy setup.