We have already recommended that you get a TV wall mount to get the most of your new HD TV. Having done this and set your TV on the wall, you now need to calibrate it.
The key thing to remember is that manufacturers’ defaults are not necessarily the best settings for you. In fact, it is highly unlikely that they are. Those settings are honed to achieve one aim – to make the TV stand out from all the others in the shop. If you acknowledge this fact, it is apparent that you have to make some changes.