Just a few thoughts on Season 5 that I haven't seen anybody else make. So sorry if I've stollen your idea! :P
I see that there has been a lot of talk about Desmond returning to the island for some unknown reason. Why? Is this because of what Eloise Hawking said to him in Episode 316 while in the Lamp Post? I think She said something like "The island isn't finished with you yet" but that doesn't mean that he has to return. Maybe what she meant was the island isn't finished with you yet because you're are going to get caught up in something that is bigger than you, bigger than all of us and the ex-leader of the Others is going to shoot you? As She says to Penny in the hospital for the first time in a long time she doesn't know what is going to happen, she was unsure as to whether Desmond would live or die, I think this is proof that what she said to Desmond in the Lamp Post doesn't mean he had to return. If Eloise Hawking knew that Desmond had to return then she should have also known that he couldn't die when Ben shot him.
Also, am I the only one that would feel cheated if the Incident is somehow avoided and flight 815 landed at LAX? Surely that would be a complete waste of everyones time. I'm a firm beleiver in Whatever happened, Happened. The incident will still happen, Desmond will still forget to push the button and 815 will still crash. However I have heard some people saying that when the Incident occurs, then the Losties that are stuck in 1977 will rejoin their original time line in 2007. What proof does anyone have for this? Why couldn't the people who are in 2007 and in 1977 skip through time again and end up in a different era, such as the 80's. Also if this was to happen then maybe the island would skip to a point in time where the story of the Black Rock could be explained better or we'd find out what the Statue is? Maybe the island could skip to a time where Daniel Faraday is still alive and Jack and Kate could tell him not to go into the Others camp, there by avoiding his death and changing everyone's future. (Yes, I know "Whatever Happened, Happened" OK, maybe I'm kind of on the fence on this one. It is Lost after all, anything is possible!)
Anyway, let me know what you think about this, I'd love to get some feed back.