Just watched the latest episode, Ab Aeterno (which was brilliant by the way) and here are some ideas i have drawn from it.
Judging by the direction the show has been taking since the end of Season 5, it seems only logical to assume that we will get the faith ending of LOST.
I think that the Island could be The Garden of Eden. Jacob kept saying that it was necessary to keep this "evil" from escaping and entering the outside world. It's obvious that the island posesses mysterious magical properties.
I also believe that Smokey could be the Serpent mentioned in the Bible. There are clear similarities between Smokey and the Serpent, such as luring and using deceit to fool mankind.
In Genesis, the Serpent is merely portrayed as a deceptive creature or trickster, promoting as good what God had directly forbidden, and particularly cunning in its deception.
Smokey's primary objective is to get off this island and to the outside world. His intentions are to prove that mankind are corruptable by being deceitful. Smokey lied and said Richard would get to see his wife again if he killed Jacob.
We also saw Isabella on the Black Rock in a dream-like state for Richard. I believe that this was merely Smokey taking the form of her. The Serpent talked to Eve previously as an apparition in the form of an angelic angel...
Just some ideas i felt like putting down after the episode, let me know what you think :P