I am looking at replacing my old, outdated, barely limping along NAS. I am leaning towards using Unraid over FreeNAS just for the simple fact of being able to add drives as I please. I will probably run Plex, house some smb/cifs shares, and possibly store VMDKs for my vmware lab on it. My budget is around $500-600 (diskless).
Here is what I have put together for a possible build, let me know how bad I screwed up.
https://pcpartpicker.com/list/WWKhfH