I am a huge Lost fan and recently watched the finale for Season 5 entitled "The Incident". It was a two hour special and as always supplied more questions than answers.
First of all, the answers:
We find out the statue is of an Egyptian God, not one of the Losties as many had speculated.
We find out who Jacob is.
Not a mystical creature or an old man but a rather young handsome man. We discover that he had visited many of our favourite characters in the past and helped them get to the Island by psychologically nudging them along. This is especially true in Hurley's case where he straight up told him to go back to the Island after Hurley is let out of prison. We also learn that Jacob has a rivalry with another man as we see at the beginning and discover he has been helping people find the Island for many years judging by the old boat, presumably The Black Rock. 
We find out what is in the metal box. During the episode I started to think that the hydrogen bomb would somehow be in the box. It was just the way they where tying in the 1977 scenes with the 2007 scenes. I was thankfully wrong.
A lot of people said it would be Widmore in the box. When they where emptying the box out, I was really worried it would be the bomb or Widmore because I wanted a surprise. All I can say is that is what I got. First they show a dead body roll out, not showing who it is, keeping us all on the edge of our seats. We soon discover it is John Lock's dead body in the metal box, the same man that just walked down under the statue to kill Jacob.
This means the man we believed to be John Locke the entire series from the point the Agira flight landed on the Island was indeed an impostor, most likely the man we see talking to Jacob at the beginning. The man who says he wants to kill him.
Now for the questions:
Is Jacob good or evil? We see him in light clothing and his enemy in dark which is the universal idea of good and evil. But his enemy says how Jacob has brought people to the Island and how they always come and corrupt it making Jacob seem like a man who does not want what is best for the Island. This contradicts what we have been led to believe in the past.
At the end of the episode a dying Juliet smashes a rock against the un-exploded bomb core leading it to explode (if that is what the white light and loud noise was) which according to Faraday's (revised) theory will send the Losties back to the future and they will never crash on the island. I have many issues with this theory and have my own theories on the issue.
First of all we have always been told that whatever happened, happened and that you cannot change the past because it already happened. We learned this off Daniel Faraday early in the Season until one day he decides that we really can change the past, just before he dies by the gun of his mother.
If we think logically even if they could change the past, blowing up that bomb would still kill their present selves only their younger 1977 counterparts will grow up and never crash on the Island. Then the cycle continues as then they would never go back in time if they never crash meaning they would never prevent the Incident from happening. This would mean the Swan would still be built, Desmond would still not hit the button and their plane would indeed crash on the Islan on September 22nd 2004. It's the traditional time travel paradox.
One thing is for certain, there is no logic in the theory that blowing up the bomb would magically send the gang back to 2004 without any memory of the events on the Island and they would all saftely land in LAX. That just makes no sense.
Just as we discovered that dead really is dead as the episode "Dead is Dead" hinted towards maybe we should believe that the episode "Whatever Happened, Happened" is also a hint that whatever happened really did happen. I meant that's what Farady told us. maybe he just went crazy, or maybe he knew that he would have to die and convince Jack and the rest that they could change the future so that they would blow up that bomb. Why? Maybe the bomb is the Incident, just as Miles says. That would mean farady would have to convince Jack to cause it as thast is what he always did.
If this is true however it means the characters all died which doesn't seem a possibility as we still have a whole Season to go.
I'm not sure how this is going to turn out but I really hope the writers do something intelligent and not a "they all jump forward in time to 2007 to fight eveil Locke just as they bomb goes off" because that would really suck.
We'll have to wait until Season 6 to find out. Here's the Promo.
