Here are some great tips from Home Theater Blog: http://www.hometheaterblog.com/hometheater/2006/05/how-to-wall-mounting-a-lcd-or-plasma/

Important Notes: If mounting the TV on the wall, you'll want to be sure to install the mounting bracket directly in the wall studs. As far as hiding the cables, you'll need to use a sheetrock saw to cut out the drywall enough to install a cable wall box -- where the TV is installed, AND where the AV equipment is located, so you'll be able to make the cable connections {you may need to fish the cables from one area to another}. I strongly suggest you consult with a media system installer or electrician before you proceed. You may find that it's easier and worth the price of having a professional do the job!

There is an AWESOME product (I don't have it, but keep looking at the catalog) from Design Within Reach. It's a media storage system that is ready to paint or wallpaper so it will camouflage itself against the wall. All cables will be in the back of it. It's not a cumbersome bookcase. It's very flat and streamlined.

http://www.dwr.com/product/muro-media-storage-unfinished.do?keyword=tv&sortby=ourPicks

Thanks for all useful advices. Im much interested in Carli8020 advice. Will look for this product. Happy new year to all houzz members