If the mantle isn't too high -- it's a great idea. The biggest benefit is that you get to use all the other walls in the room for seating. You also get to face a warm fire while watching movies. Have you bought your fireplace yet? I just installed a ventless fireplace, it kicks out a lot of heat -- actually heats the basement. I didn't install a tv above it, but I have my audio equipment on shelves above it.