I am having my home prewired and I am pretty sure there will be enough slack from the prewire that they put in the cieling to pull down the wall for the 2 front channel speakers to be put in the wall next to a plasma tv I have. But if not would it be a disaster to put the front channel speakers in the cieling? I will have the center channel speaker above or below the TV. Thanks for the input.
Ideally the front speakers should be at ear level when watching in your favorite chair. If that is not possible and ceiling is your only option, then there are a number of speaker manufacturers that provide aimable tweeters in their ceiling speaker. Some even allow the whole speaker to be positioned at a small angle to direct sound toward the listing area. It would be very undesirable to mount a non-directional ceiling speaker as the sound from the speaker would be directed into the carpet where you loose content, get reflections and delays.
If sound is all your looking for, then any arrangement will "work". However, "movie effects" are designed for a standard placement of each speaker.
Ceiling speakers are fine for background music, but if you're planning a HT, avoid those at all costs for the reasons listed by Phil. Those are huge reasons and your chances of having a high performance HT soundsystem are slim and none with ceiling speakers.............and slim left town.
If flexibility and performance are of any concern, I'd avoid anything that is in-wall.
Paul, did you mean to say anything that is in-ceiling? Because there are a number of speaker Manuacturers today that provide some really high end, built-in speakers. This past year at CEDIA I witnessed several that changed my mind. Just curious.