LOST

I actually viewed this whole thing a little different....

They all died in the plane crash....but noone wanted to accept the fact that they were dead...or they needed to come to terms with something in their life in order to move on. The whole island is purgatory...either you are good or evil and you move on when you are ready to. The 'Others' were the 'good' trying to help people move on from being in Limbo (like children who do not have 'sins' to repent for) The Dharma initiative are those who are either not allowed to go to heaven..or will not accept death so they are trying to find a way either off the island (out of purgatory) or into heaven or they dont want to leave because they will be dead so they do what they can to 'keep the island alive'. The flash sideways we see this season is what the characters felt that they wanted or needed to happen before they died (jack wanting a son, claire having a baby, sun and jin getting pregnant, etc)...These are the things that 'may' have happened had they not crashed.

When each person on the island 'died' it was really because they came to terms with something or repented for their sins ( ex. Boone died when he realized he was in love with Shannon,)

Thats my take on it...but maybe the point is for everyone to have all these questions and theories

Did anyone watch the jimmel kimmel special afterwards.? I just finished watching it.. So like many posted here and in the BHB post:
Jacks take on it, was also that he was ALIVE when they crashed, and the sideways was the limbo period. when they finally died (not during the initial crash)