In one of the press talks at the E3 game show, Richard Irving from the Xbox Engineering Team revealed a major update to the Xbox One UI end of this year.
The new UI has a vertical orientation (which is a change from the previous horizontal one) and makes use of a quick navigation panel on the left hand side. Even from a game this navigation panel is quickly accessible by pressing the Xbox button twice on the controller. Another cool addition to the platform is Cortana. Cortana can be accessed throughout the interface and can help you out connecting to your friends and more.
For the complete listing of features, read the article on Xbox Wire.