We don't watch a lot of TV; maybe four hours a week. But we noticed in the past year or two that a few of the shows we enjoy have muddy soundtracks due to speech being mixed over top of background music and various sound effects that makes the words almost indistinguishable. My hunch was that it was due to the increasing popularity of surround sound mixing, so much so that the producers had chosen to disrupt the viewing experience of plain jane viewers relying only on their television's built-in speakers. But for various reasons (largely - having better things to do), I never bothered to confirm this hunch.
I took advantage of a Boxing Day sale to pick up a set of surround sound speakers and a Dolby-enabled amplifier; nothing fancy. After many hours of threading wires behind drywall and through the basement (reminding me that I really do have better things to do), we sat down to watch an episode of one of the offending shows (Torchwood). And the difference in clarity (largely due to the separation of the sound into front left, center, and front right channels; the back left and right channels have much less impact) was immediately evident; Lynn mentioned it within five seconds of the beginning of the show.
Our household has entered a new age of audio-visual enjoyment. I know I've been manipulated into buying more electronics, but at the same time - wow, what a difference. It makes me want to watch all of season one of Battlestar Galactica again.