I am 3 days late, but whatever.
Where do I start with a show like Lost? I was pretty happy with the ending, considering I had been disappointed most of the series. I would get so fed up with those freaking unanswered questions, I even had a paper and pen to write down questions as I watched the episodes. Fortunately, someone had accidentally thrown it away when I left it on the coffee table. I'm really glad that I didn't have that paper full of questions, otherwise I'm pretty sure I would be pissed that many of the questions were left unanswered.
So yes, I was content with the ending. I was confused at the last scene even though I had my own thoughts, but after some thinking to myself, hearing what Matthew Fox had to say on Jimmy Kimmel, and some scouring of the Lost Forums, I confirmed assessments. So here is my interpretation of the whole thing, but most specifically the last scene. Everything that happened on the island happened: they crashed, they encountered the smoke monster, they time traveled; everything happened. And the alternate reality that we saw throughout this last season of their lives if the plane hadn't crashed is their waiting room to go to heaven. When everyone met up in that church, they were all dead. They died at their respective times, of course, not all at the same time. Jack's father also said that they were waiting for him, so I think (as does Matthew Fox) that Jack was just the last one to realize his death so that he could finally let go and move on into heaven or wherever.
I totally admit I did cry as I watched the last episode, but who freaking didn't. The parts of everyone remembering got to me the most, especially Claire and Charlie. awwww! So sad. Okay I'm done, but there's my two cents. Despite that I was let down most of the series, this ending was perfect, and I say perfect because I'm not sure how else they would have ended it. Yes, they didn't answer every single question, but those questions were not what the show was all about. The show was about the people, who they were, where they came from, who they became and the ending pretty much summed all that up.