There are two moments I believe center around the eventual "answers" to the show. The basic question to the show originally was "where are they?" Well they answered that this season when we were told the island was always moving and that it an electromagnetic hot spot. So the real "answers" people are waiting for will be how it all turns out like and good thriller.
So I believe the two biggest clues were Faraday crying and the discovery of Adam and Eve.
Faraday's scene is important, because he cries when he sees the flight 815 "discovered." When asked why he is crying he says "I don't know." This to me implys at the overall emotion of the series end. That our beloved show will end as a partial if not total tragedy. I am under the belief that as Faraday's conciousness is jumping around Desmond will save him by being his constant and that is what damages his memory. I believe this revelation will occur by the end of this season.
Adam and Eve on the other hand I believe are important simply, because of who I think they are. I do believe the two skeletons will be Jack and Kate. How and why they got there I obviously don't know, but Jack obviously doesn't have any desire to go back to the real world so him dieing on the island would make sense. Also I am a believer that Kate and Jack will end up together so being left with eachother would also make sense. Also the fact that he took the stones with him off the bodies when he left and the recurring themes of those stones in the series. (Locke's eyes in one episode and his games with Walt.) The creators have also said Adam and Eve will "prove" they've had an ending since they started.