In the future, everyone will have a nose stud or two.
One on each side of the nose, powered by microturbine in the nostril, with lots of gadgetry built into it. Obvious gadgetry include a head-up display projected directly onto the retina of each eye. Bluetooth-equipped, they will be able to display anything from personal data, to commercial advertisements, to the personal avatars floating above the heads of other people around us. With a built-in IR camera, they will also allow us to see in the dark. This will be the best technological solution to inefficient artificial lighting in the future.