I'm very much a LOSTIE. I watch every episode, discuss question about the plot, and read Lostpedia almost daily. I've even added the 1st 3 seasons to my wedding gift registry. If you're a LOST fan too then you watched this weeks 2 hr season finale and have a whole host of questions.
After watching the show so far I have a few theories. The island, Jacob, Christian Sheppard and now Claire are all the same. They try to keep the island secret and carry out it's will. I think the island is a representation or manifestion of God's will on earth. Just like in the Bible, God had a chosen people the island has a chosen people (the Others).
Just like Jacob of the Bible was a man of faith the Jacob of the represents faith. Those who follow Jacob (Ben, The Others, & now Locke) do so by faith. Whereas those live by science (Jack, Widmore, Dharma Initiative) try to control things. The DI used stations to control the islands natural properties (Swan & Orchid stations). Usually with dire results (ie: the purge).
Just like God, the island offers people redemption. Or more specifically to choice at seeking redemption. Those who fail intially but then redeem themselves through actions are taken/die (Eko, Charlie, Michael). But those who follow the quiet voice of God inside all of us from an early age are given the chance to accept their fate and used as instruments of the island.
How do the ancient things on the island (statue, the temple, smoke monster, the orchid wheel) fit in with the outside forces (Hanso, Widmore, Paik, DI)? I think that's what the next 2 seasons will be about. In the end, ALOT of the small questions will go unanswered (at least by the TV show.. the producers may fill in the gaps through podcasts). It will answer major questions about the island, the numbers, the DI, the others, and why Oceanic 815?