So, I realize this is really late, but if any of you watch the show lost this is a topic for you to talk about the end of season 5 and what you think will happen in Season 6, also you can talk about other Lost related stuff.
I have one theory about the white light that occurred after they detonated the hydrogen bomb, I think that the white flash was similar to that of the earlier episodes where they island (or just the people on it) were travelling through time. I think that it was the group of them stuck in 1977(year?) travelling forward in time to the point where the other people on the plane are.
I also think that Charlie will be coming back :D I think the guitar Jacob gave Hurley was actually Charlie's. Also, there was no real reason that Charlie die, he could have swam out of the flooded room that he supposedly died in through the hole left by the grenades explosion. And if he did die he might still come back as another embodiment of the smoke monster/Guy in Darkly colored garments sitting on the beach talking to Jacob.
I also think that the 6 season will be about the war between Jacob's follower and the other guy's followers, people such as Jack, Kate, Sawyer, Hurley, etc. will have to choose sides.