I have to go with the sixth gen on this one. Ico, in my mind, is the best Sony first-party game of all time. Jak and Daxter: The Precursor Legacy is the best 3D platformer not made by Nintendo, Rare, or Double Fine. Santa Monica gave us two great God of War games, and Insomniac gave us an awesome trilogy of Ratchet & Clank games.
I think the sixth gen really learned from the growing pains of the fifth. Starting with the seventh, Sony's first-party studios started to lose touch with what made the sixth gen so successful, and the eighth gen has proved to be more of the same.










