I have had Plex running on an Ubuntu based machine in the past and using SMB shares any Windows machine could copy media on to local drive.
I now run Plexe on my Qnap NAS. Far more efficient for us and uses an appliance approach removing another PC/Server out of the mix. We have somewhere around 2.7TB of video and music on the NAS now, all front ended by Plex. Clients are on my Samsung Smart TV and our Roku. Also can connect via DLNA from the PS3 and Windows machines running a media player. However, be aware that some platforms can’t play all media types so your “server” may need to transcode on the fly or direct stream instead of playing locally on the device. This is an issue on the PS3 for example.
We’ve had Plex in our mix for about 5 years now after abandoning XBMC over stability issues.