Typography guru Erik Spiekermann and his wife, designer Susanna Dulkinys, hate clutter. That’s why they love the super-sleek Berlin domicile they constructed to have just the right lines—and a host of energy-saving features behind the scenes. The stainless-steel Bulthaup kitchen "cost as much as a small house," said Spiekermann, though he did get a discount: Bulthaup is one of his clients.