I was never a "Lostie," or one of the people who followed the show Lost since it started back in 2004. I have friends who recommended it highly, but I was often busy when it aired and it seemed, in the middle seasons at least, to be a show with a really steep learning curve and I'm pretty lazy when it comes to things like that. Got some spoilers here, so you've been warned.
I had watched a few episodes this season at the gym, since it was on when I was there in the evenings, and as I've mentioned before, I caught up with this final arc pretty quickly. I knew enough that I was curious to see how it would all end, so I did watch the finale. One thing that interested me was that, after having read his dialogue for a few months via the closed-captioning on the gym TV sets but not heard him for about six years, I had forgotten that Matthew Fox had such a nasally voice.
Reaction to the finale has been as most finale reactions are: Mixed. Some people loved it, some people hated it. The lovers seem to focus on the "happy ending" flavor of the scenario for the characters they'd grown to care about. The haters seem to think that the show's writers -- or in the case of one resident of the very summit of Mt. Dudgeon that I read, "writers" -- should have answered more questions about what the island was, and what was going on with certain characters who hadn't been around in awhile, and so on and so on. Or at the very least, answered them differently than they did. It almost seems like they figured the show had to be way smarter in order to entice intellectuals such as themselves to watch that most plebian of entertainment media, television, and they're angry because it turns out some of the answers to their questions were pretty simple, and some of them were just left up in the air. And some folks had both reactions, with their love focusing on the happy ending and their distaste on the lack of answers.
As a non-Lostie, the lack of answers didn't matter so much to me because I didn't have years invested in trying to figure them out. I did find the final vision of the characters, gathering in a church setting before headed on to the life after this one, fascinating. My guess is that they are there together after they have died. One character points out that there is no "now" where they are, so they are together no matter how many years may have elapsed between their real-world deaths. The strong bonds they built during their island experiences mean that they have forged a community, and it's as a community that they will move on when they have come together.
The way they get to that time together is apparently through taking actions or envisioning themselves taking actions that help set right a lot of things that may or may not have been wrong during their lives. When they have done that, their idealized self somehow integrates with their real-world self and they are ready to move on. The "sideways" alternate universe that this season has shown us, where Oceanic Flight 815 never crashed, is a sort of Purgatory-like existence that helps them overcome those things that they apparently believe were wrong with their lives before they died. It's not a very harsh version of Purgatory, though, as their experiences are designed less to purge them of wrongs as they are to allow them to right them.
It fascinates me because it's a spin on C.S. Lewis's The Great Divorce, in which Lewis imagines a man is given a vision of both hell and heaven. He sees hell as endless gray city, populated by joyless folk who labor away at meaningless tasks and who make the city so immense because they are unwilling to ever live near each other or have anyone interfere with their lives. In essence, Lewis suggests we make our own hells, and the irony is that we do so as we attempt to create our ideal lives, or paradises. Lost has its characters create their own purgatory, then, by comparison, but an interesting factor is that they are ready to leave it and move on only when they reunite with their island community. Jack first warns the crash survivors of the need to work together in the fifth episode of the show by saying, "But if we can't live together, we're going to die alone." Other characters will echo that phrase through the show's run, and it's the title of the season 2 finale. In the end, the characters of Lost reach their heaven -- or whatever it is that comes after this world according to their universe -- when they rebuild the community that gave them life when they were in their time of greatest need.
Although I wasn't one of the hip and relevant preachers who successfully or otherwise tried to shoehorn the series finale into a Pentecost sermon just because both events happened on the same day -- I can preach a confusing sermon on Pentecost just fine without Lost's help -- I think that final scene is a close enough allegory to the body of Christ to make me happy with the show's end. If not happier than I was when I watched Newhart, at least a lot happier than I was with Battlestar Galactica's windup, anyway.