While I'm not sold on low couches, I love beds that are on or hover just off the ground. Done thoughtlessly, a mattress on the floor will look like it belongs in a sloppy dorm room, but a well executed low bed is relaxed and looks effortless.
I appreciate a nice big brass or upholstered frame, but, for me, a bed close to the ground feels much more inviting.
The look can tend more modern, but Images 2 and 9 show how it also can work well with antiques and worn-in materials. How do you feel about low beds? If you're into it, check out Laure's tips for making the look work in your home.