Playstation gamer's, what's your all time favorite 1st party Sony game ? and Why ?

[JustThatGamer]

God of War III

The God of War series is the reason I buy PlayStation consoles, it's my favourite series. I think 1, 2 & 3 are up there with the best games of all time and GoS & CoO are up there with the best handheld games of all time.