If you don't count the front and back entryways, our apartment has eight doors that are spread through the hallway and various rooms. Right now all of them (and the walls between them) are a bright white. This seemed like a grand idea when we moved in, because the apartment felt crowded and small.
But white paint and simple window treatments did wonders. And we recently pared down our possessions and consigned the clutter (including hundreds of books and CDs) to offsite storage.