Palazzo Doria Pamphilj is one of Rome's great private art collections, still held by the princely family whose name is on the door. The galleries are dense with Renaissance and Baroque painting, including works by Titian, Raphael, Velázquez, Caravaggio, and Bernini.
It is grand without feeling as processed as the Vatican Museums. Go for the art, but leave time for the palace rooms themselves and the audio guide, which gives the collection a family voice rather than a textbook one.