In this kind of installation, you need, at least, 2 things :
- A media server ==> your question
- A player (at least one but you can have one for music, one for videos on your tv, ...)
Communication protocol between server and client is important and there is an open standard called UPnP that does a good job and works with a lot of different clients. There are other (ie Airplay system in the Apple world) that i do not know.
UPnP Server can stream Videos, Pictures or Audio
So if you run an UPnP media server, you'll be able to :
- stream all multimedia content from your desktop, laptop, netbook ... running windows or linux
- stream all your multimedia content from smartphones (iPhone, iPad, Android at least)
- stream all your multimedia content from video game console (PS3 and XBOX360)
- Stream your audio and video from compatible TV BOX (Boxee Box in last version, WD HDTV Box, ...)
- Stream you music on compatible Hi-Fi system
- Manage what is playing on what client with your iPod or iPad using PlugPlayer
Most of recent NAS Systems offer UPnP server feature (and others like download station, backup, ...), mine is a Synology and is based on Linux. I can connect to it using telnet or ssh, it's not ubuntu but its a Linux.
My NAS contain all my files and I can access them from everywhere (my home network and even from Internet) using any compatible device.
Hope this help.