Spain's capital offers the best of food, art, architecture and nightlife. For the best address in town, book a stay at AC Palacio del Retiro, set on the Parque del Retiro. For Old World splendor and a star-studded past, check in to the Gran Meliá Fénix. Foodies will want to score a room at Hotel Hesperia Madrid, home to one of Spain's top restaurants. Design lovers will appreciate the details—old and new—at Urso Hotel & Spa in the hip Salesas neighborhood.