Alright so I've been trying to explain to my family and friends what I think is happening and why we are seeing 2 different stories, one where the reset worked and one where it didn't and this is what I've got:
They're both real, and the best way I can explain this is using what Sawyer said as an example, at some point last season Sawyer made a reference when he was in 1977 that his father killed a his mother one year ago in 1976(while he was on the island) and he chose not to go and intervene. So that means that there is 2 Sawyers, 2 Jack's and anyone else that was born by 1977 in the world (one older on island, and one younger off island). That is the basis of this theory.
I believe that when Jack, Sawyer and them changed the future it worked, but not for them. Instead for their younger selves when 2004 comes around they will land safely in LAX and never end up back on the island because they sank the island in 1977 when they detonated the bomb. But unfortunately for older on island Jack and the rest they don't just get transferred back to the day of the crash and land safely because that's not what happened to them they crashed on the island and what happened has to happen, instead they end up on the island just back in their correct time 2007. Therefor we have to different realities going on that are both real one where the island still exists and one where it does not. I know that doesn't make a lot of sense but no one really knows what would happen if you used an H bomb to release a massive pocket of energy from the earth so it's hard to really argue against it.
So now I believe we will start to see both how things would play out on the island and how things would happen had the plane never crashed. But there are still a few twist, Desmond on the plane, Shannon not on the plane, Hurley now lucky and I'm sure we'll see more. I believe the "twists" off island are all because the past was changed from 1977 on. So who knows what Desmond would be doing in 2004, apparently he's going to LA from Sydney, to me it's become clear that he is still destine to do something with these people. I also believe what ever it was that cause the numbers to become cursed must have happened post incident because now there is no curse and Hurley has become lucky, he also probably didn't hear them in the mental institution (since there'd be nothing for Leonard to be so worked up about) he probably just remembered them like Jack somehow remembers Desmond, like a deja vu feeling.
I also read on here last night someone thought that Juliet was going in and out of realities as she was dying and that last this season we would see her ask Sawyer if he wants to go for coffee I thought that was brilliant that it kind of tied in to what I was thinking so thanks to who ever that was
Sorry if this is scattered of hard to read I made the mistake of thinking it would be easier to write this high, it was not