First off, a media room is one that has a projector and screen, not a TV. Second, the guy didn't have surround sound speakers installed in the room, he had speakers.
The wall is not "equipped for an LCD." -You have a spot where you can mount a monitor.
Finally if you do have odd shaped holes in your wall, do you have a-hole somewhere around the area below the spot you would put the mounting bracket for a center channel?? --No center channel--- no surrounds sounds speakers.--
Go to a stereo shop and let them show you some options. Ideally, let them see the room you are describing.