Not all of the thought I will put out here are my own; in fact, I have copied several of other peoples' comments from Dan Carlson's Pajiba article. These are mainly to start conversation, ask/answer questions, and propose theories:
*(directly from DC's recap) There are hundred of things to think about before the series returns next year — January never seemed so far — but here are some of the basics kicking around my brain: I believe the island possibly relocated geographically as well as temporally. The island’s disappearance was because it shifted forward in time, as explained by Halliwax in the orientation video. Ben moved the island on day 100 after the crash, in late December 2004, and walks into the Tunisian hotel on October 24, 2005, so it’s reasonable to assume that the island also “jumped” 10 months or so into the future. But when Ben visits/-ed Widmore at the end of “The Shape of Things to Come,” each man swears to destroy what the other holds dear: Ben says he’ll kill Penny as vengeance for Alex’s death, while Widmore vows to reclaim the island. But Ben replies, “You’ll never find it.” Since Widmore had already found the island and sent the Kahana there, it seems reasonable to assume that he won’t just check the same location and find it all over again once it “reappears” after jumping to the future. So he’s got to begin the search again, which means the island moved to another spot on the planet as well as another time. Also, because the relocation took the main island and the smaller one, there’s a good chance that Daniel and the raft went, too, if only because it’d be a shame to kill off Jeremy Davies. Additionally, though the ship exploded, we didn’t see Jin’s body get blown away, and though he probably bought it, until the show ends, there will always be a part of that hopes he somehow will be reunited with Sun. I mean, it’s “Lost”; even if you see the corpse, that doesn’t mean they won’t come back.
*I think Widmore has moved the island before, which is why he hasn't been able to get back. Also, I think Charlotte, Miles, and Faraday are all Dharma kids, which is why a ship of Widmore's finally found the island after all his years of searching (under the idea that certain people belong on the island and the island brings them there, the same way Ben will use the Six to find the island again).
*Then I also started thinking about the Hydra island (the second island) and how it seemed to have disappeared sometime after Sawyer and Kate escaped. Remember in the original version of the Orchid video (the one shown at Comic Con), they put the bunny in the Casimir Effect chamber, which was supposed to move it forward in time (much like what Ben is about to do to the island), but there ended up being two bunnies at the same time. So I wonder if the Hydra island was just the original island, which was duplicated when Widmore moved the island.
*Someone at TWoP mentioned the possibility that there are two Lockes running around now - one being dead Jeremy, and I love that idea (like the bunnies who doubled in the full Orchid video - keep them away from each other!)
*I really hope that they do something cool with Walt, and finally answer what used to be the biggest damn question of LOST - exactly WHAT is so special about Walt?
*I also think that Widmore was the last person to move the island, and the theory that Daniel, Charlotte, and Miles are Dharma kids would go along with that quite nicely. Maybe Daniel doesn't remember his Dharma past. That makes his scene earlier in the season, where he didn't know why he was crying while watching footage of the 815 wreckage, all the more intriguing.
*Yes, Jeremy Bentham is preserved in a box - but the head in the box is wax. His real head is somewhere else (because it used to be kept in the box, but it got stolen a few times for pranks). So, we have a man in a box, whose head (the only thing that makes us think it's Locke) is not real.... hmmm. **Look up Jeremy Bentham online to understand the referance**
*Was I the only one who felt there was more to Ben's goodbye to Locke when he said, "I'm sorry I made your life so miserable"? It seemed like there was more meaning there than just what transpired on the island. Maybe I'm totally off base but it seemed that way to me. **Maybe Ben knows that Richard wanted Locke all along, so he knows about the intricacies of Locke’s life leading up to his arrival on the island…
*What is up with the crackers? It was a cute joke the first time they appeared, but now they're back again. It makes me wonder if the writers have something in mind with them, or if they just enjoy watching fans obsess over minor details that actually mean nothing.
*Have you ever heard of the musical "The Last Five Years"? That is what I think of when people describe how the flashforwards link up to the "present". In the musical you see the five-year love story of a couple (from dating to divorce), but he tells the story forward, and she tells the story backward. Her first song is about being left alone, but then he sings this great song about meeting a shiksa goddess, so the story meets in the middle and you see the perspective of both sides.
*If Miles is really psychic, and not just able to speak to the dead, then is it possible that he knew the freightor would explode? If so, it is execessively douche-y not to warn others. He may be a champion prick, but he is a fascinating character, and I want to see more from him.
*I think I read that the writers hinted at the "sky turning purple again" - is that what happened at the end? Did the electromagnetic pulse move the island? If so, it leads one to believe it moved before, when they crashed... so who left? The real Jacob? And that is why he is spoken for by Christian? Head hurting...
*OH, and in the press conference there was a photo of them landing on Membata (which is Indonesian for "doubt" or "uncertainty") - who took the picture? It seems insignificant, but I dont think it is. Someone was expecting them to be there, because I didnt see any fisherman with digital cameras...