When we say home theater audio, the first thing that comes to mind is Huge speakers with mind blowing sound, massive receivers with rear panels adorned with a multitude of inputs.
However, everyday, people Google home theater and inevitably end up on this forum, many with no idea where to start, or what to even consider good sound.
So a bit of advice i have been offering for several years now to people who want to test the waters of good audio for beginners, has been to invest in a simple good sounding inexpensive set of 2.1 computer speakers, and plug it, with the use of an adapter into the "audio out" jack on the back of the television set. In the event the television didn't have it, there was always the option to plug it into the DVD player or VCR.
In general if you are coming from the built in speakers in you TV, be it a CRT, LCD or Plasma, on average, a Pair of Logitech S220, or X230 with have notably better sound than the built in speakers for under $50 USD. They will have a far better mid range. crisper heights and a lot of bass at varying levels which a lot of built in speakers lack altogether.
The only real downside of this is that there is usually no wireless remote included with speakers at this price-point to adjust the volume from a distance away (your couch).
NOTE, If your TV has a "Headphone Out" jack on it, if you plug the speakers in there, instead of the "Audio Out" RCA jacks, and you should be able to use the TV remote to adjust the volume on the External Computer Speakers you are using.
Anyone willing to recommend more speakers preferable under $50 USD; $100 USD Max, please state below with a short 4-5 line personal review, it can be longer if you so desire.
My picks are: -
Logitech X230/X220 (Out of production)
Logitech S220 (Well rounded with good sound at varying levels, not great with heights, excellent mids and bass,but at this price is absolutely unbeatable)
Logitech Z-2300 (Can be found for sale for $100, but is lacking in mid-range and not perfect for dialogue but excellent sound otherwise)