At first I was disheartened that the finale didn't explain all the millions of loose ends about the island and tell us what the eff was going on there for all these years. But then I slept on it and have reached a conclusion that answers everything in a way that leaves me satisfied.
There are many differing opinions on what the events of the series and finale actually mean, so I add my opinion to the roster...
The Island and the Characters
- Everyone on Oceanic 815 died when the plane crashed in the very first episode
- The island is a place between life and death (a sort of Limbo) where those who die have to sort through the baggage of their lives and have certain experiences and learn certain "lessons" before they can move on to the next phase:
- the main characters in LOST entered Limbo (the island) at the same time and were in a sort of death co-hort together. They were able to learn about their own lessons by experiencing dramatic events with each other. All the things they experienced on the island were very real and therefore significant and memorable - probably more memorable than anything they had experienced in life because of the profound meaning these experiences brought to each of their "souls".
- Because of their bonding experiences in Limbo (the island), the main LOST characters created a place where they could all meet when they left Limbo but before they moved on to the next phase - I'll call it Purgatory even though it is not exactly like the catholic definition of it. This was the place where Desmond was the guide bringing them altogether - some LOST fans call it the "flash sideways".
- Jack being the sort of character that he was could not "awaken" from Purgatory until everyone else made it there which is why he was the last to be ready to move on.
- During the credits of the finale, the wreckage of flight 815 was shown on the beach as if it had never been touched post-crash, this led me to believe they all died in the crash (although apparently some bloggers claim that this isn't meant to be a part of the story, just a visual for the credits but for me it was a part of the entire experience).
- The island was so strange with time shifts, smoke monsters, glowing light, good and evil with shades of grey... all of this can be explained away if this is a place beyond life where all the drama is there to provide experiences to the souls of the LOST characters to help them achieve some sort of enlightenment
- Jacob was the guardian of this place where everyone wanted to escape
- The Others and Benjamin were already on the island when the main LOST characters arrived and they were not interested in leaving Limbo - meaning they weren't interested in participating in whatever experiences or lessons they needed to learn to move on with death (except Juliet which makes her different). The LOST characters pulled Benjamin out of this and started him on his way but as he admits at the end, he isn't ready to totally move on as he has more work to do in Limbo.
- Desmond kept trying to leave but always kept being brought back until he was able to move through his lessons...
- No babies conceived on the island could be born because it was Limbo - no new souls are born in Limbo.
Michael Carmichael of the Huffington Post has a similar take with reference to Eastern philosophies rather than Catholicism's Limbo and Purgatory:
Six years ago, the most compelling series in the history of television began after a plane crash when Jack Shephard opened his eye in a bamboo forest on a Pacific island to see a dog called Vincent running towards him. On Sunday, this most compulsive series in television history ended with Jack Shephard closing his eye in the same bamboo forest with Vincent next to him...
...All of the gripping psychodrama of the past six years took place in the mind compressed into the twinkling of an eye of the wounded hero. The hero resolves his dharma, his duty to the universe, in a vast psychic collision with the confused minds of the other passengers aboard the doomed flight and a broader cast of supporting characters drawn from their lives. The island is now revealed as the dao -- the natural platform of reality where humanity resolves her duty to dharma.From: The End of Lost: Death, Dharma & the Dao