One of the best episodes ever in LOST history. It just had everything: answers, character development, new mysteries, action, the Monster and even a death of a main character.
So we finally saw the Temple (or at least a wall around it). I was always wondering if it was constructed by DHARMA or by something much older. It seems that it was built by the same people who made the Wheel and the secret room in Ben's house. And the Monster might really be the "Cerberus" of the Temple. So I'm sure now that the Monster was NOT made by DHARMA.
There were some really sweet moments in this episode, like Sawyer finding Jin. His reaction was just priceless. But there also was a major loss: the death of Charlotte. It was really painfull to watch Daniel crying over her dead body. But I'm an optimist and hope that we will see her again, because with island moving through time everything is possible.