I started to believe that the flight wreckage had actually been found. If it was staged, would they actually be able to show bodies? Would they really stage a replica plane underwater with fake dead people in it? And if they admit bodies were found, wouldn't loved ones want to bury them?? (Then countered that with the fact it was found in a trench so deep…maybe there's a reason to be given about the bodies not being retrievable.)

The flight is pivotal. If found, then either they ARE dead, or there's some parallel reality going on here.

After last night, I think we can definitively say they are not dead. How else could Naomi have flown/parachuted to the island? She didn't die first, she saw it while still in the air. Also, we've seen Others in mainland flashbacks…mostly in Juliette's recruiting. So I have to lean toward a parallel dimension--with the "box" possibly being the portal? In the "other" dimension maybe they did die.

Speaking of the box, there must be something to it--or something along the lines of its power. Going back to Walt and the polar bear, Kate and the black horse, those were really on the island, and indications are they came from the thoughts of individuals.

As for Locke's "purpose" I wonder if it really is to show everyone else the light. He worked on Boone to face his fears, he looked into the black cloud untouched, he made one of the first significant links that we've been seeing tie so many on the island together. (Was there speculation, or confirmation, that Sawyer killed Jack's dad? If so, does Locke already know that from reading his file?)

If so, then I can't wait to see the future episodes when he leads each person to enlightenment. What are Hurley's numbers about? What is the deal with the fortune-teller's vision for Claire's baby? Those are the kinds of things I could see Locke uncovering.