I have a media PC build for this purpose and more..mainly to play back to my movies and music and now MP3+G all FREE using open source software.
I also ripped all my DVD-Karaoke Disc into MKV format using H264 for video compression and keep original track and I Play back using those software below.
all store in one place on my 5TB NAS... the DVD is now one third or less in size and offer no lost in sound quality and little lost in video quality.
I use a combination of XBMC http://xbmc.org/ and media portal
http://www.team-mediaportal.com/ and Microsoft MCE remote
Took me a few months to got it all up.
I bought PC parts and build the PC, then use various software, remote, hack around and configure remote so that it all driven by a remote just like a DVD player...
this is my set up.
a PC with HDMI out hook to my Samsung LCD TV
I then use Samsung LCD optical output on the TV and plug that into my Mixer
when I want to watch movies and TV and don't want to hook through my PA system I just don't turn the PA system on and the audio will play through the TV.. if I want to sing or in a better mood for better sound I turn on my PA System and the sound automatically route to my PA system via TV optical out.
it works very well and I'm build 2 similar system for my friends cos they all love it
