Other than a gigantic screen, there's really only one enticing element of the movie theater missing from the average living room: booming surround sound. Powerful sound pulls you into the experience, projecting music and effects from all around you with clarity and volume in a way the small built-in speakers on a TV won't come close to replicating. As theater-killing technologies go, surround sound is a vital component.
Just as big, flat screen TVs have grown more affordable over the years, surround sound has become a more accessible home theater option. Home-theater-in-a-box systems, for example, include a receiver -- which handles all the various inputs and outputs for sound and video devices -- and a set of speakers for 5.1 or 7.1 surround sound. Six channels of sound are provided by 5.1 surround, including a channel dedicated to bass, while 7.1 adds two extra rear channels into the mix to increase the "surround" effect. The appeal of a home-theater-in-a-box is simplicity -- it comes with all the sound equipment you need in one package, and it's all designed to work together [source: CNET].
Audio/visual aficionados may prefer to buy their speakers and receivers separately, however, to pick out speakers with better sound and a receiver with better inputs or HD upscaling. This is typically a more expensive choice, but gives you a chance to customize your surround sound setup or expand it over time by adding speakers gradually -- perhaps to upgrade from 5.1 surround to 7.1 surround.