There is a lot of talk about the visual depth and language of the new Apple TV this week, but one of the things that I find to be most present about the design is the use of sound throughout the UI. Beyond the creation of ambiance or a sense of tonal haptic response, sound actually aids usability.
Larger objects like tiles are generally associated with a lower pitch, and smaller objects like buttons or keys are associated with a higher pitch. This means that on a visually busy screen (like say...an iTunes movie purchase screen with a less than ideal contrasting background) even before your eye recognizes that you've passed the Preview or Purchase button and landed on a "similar films" tile, your ear recognizes that you've traveled too far. Swiping left and right through a row of objects with any great amount of force will enlist surround sound to connote a sense of direction. And, chords are used with great effect to communicate movement between the home screen and apps.
These are small touches that exist within the design of a larger system. But it's also Apple at its best. It's nice to know that an additional level of sensory depth made its way into the system.