Ikea Besta units - I love the idea of a complete wall of units.Could be used in any room including a kitchen or playroom. The glossy finish reflects light back into the room and would hide a multitude of clutter. Great idea as they are not that deep and wouldn't take up much space. Placed floor to ceiling as shown makes it look built in and a lot more expensive than it actually is.
"A Sliding Bookcase Wall..." -- I have seen this attributed both to Erik Cox (at the click-through) and to Nico Sevenhuysen, both from The Netherlands, but I haven't been able to track down an original photo to prove or disprove either attribution. Whoever did it, I think I want to paint it white and add it to my house!