While your new TV might look pretty cool mounted over your fireplace, it's definitely a less-than-ideal location. We'll review some of the issues that come up with fireplace mounting, as well as some possible workarounds.
Viewing angle: HDTVs look their best when viewed head-on. If your TV's mounted high up on the wall, you'll be viewing it at an angle. Colors may look somewhat washed out, and black levels won't be as dark. Solution: Choose a tilting wall mount and angle your TV down a few degrees, so you're viewing it more head-on. Neck strain: Mounting your TV up high means that as you watch TV, you'll always be looking up -- something which, over time, can be uncomfortable for your neck. Solution: Sit in a recliner, or lay back on your couch so that you don't have to angle your neck upwards. Safe, secure mounting: The heat and smoke from some fireplaces may potentially shorten the lifespan of your TV. Also, if you'll need to mount your TV to brick or masonry, you may need to buy special hardware to securely mount your set. See the wall mount owner's manual for details.
For more tips on TV placement and room lighting, see our article on choosing the right screen size and placement for your HDTV.