We gave interior designers Darren Jett, Noz Nozawa, and Xavier Donnelly a photo of the same empty bedroom for a young professional—and then asked each of them to renovate it in their particular style.

It is the castle on the hill, the grand dame of Tinseltown, the old lady of La-La Land. For almost 100 years, Chateau Marmont has been an A-list attraction. Everybody who is anybody has stayed there, ...