Think about all the ways that you can decorate a bedroom, but the elephant (literally) in the room is the bed itself. It's the largest, most important piece of furniture in the room, and it will have its proper due. The headboard can be used in many ways to integrate the bed into the room's design scheme - or eliminating the headboard and floating the bed is a good way to free it from conventional placements.
We made a video of the integration of the headboard with the wainscoting in our hotel room this summer at the Grand Hotel de la Ville, Parma, Italy's sole 5-star hotel. The clever continuation of wood from the wainscoting to the ceiling, surrounding a decorative wood inlay, made the bed appear even more enormous than it was and gave the illusion of added height to the ceiling.