Music and HD video in any room you want. Plug your iPod into an in-wall dock and access it from any room in the house.
Everything is hidden. Electronics and all the wiring - downstairs in your mechanical room. Speakers - in the ceiling, or perhaps masquerading as art on the wall. TV's - wrapped in decorative frames, hidden behind mirrors, or out of sight completely in a cabinet with a motorized lift.
Control is easy. Handheld remote controls that you don't have to aim. In-wall touchscreens - or even your iPad - not only look "cool" but are easy to use.