LOST has very clever writers. Their literary references always bring a little smile to my face when I get one - and then when I go and read the lostpedia and pick up even more I missed I just love this show even more.
A while back in the show, as some of the survivors were sailing around the island, they saw a curious site - a gigantic stone foot with only four toes. This may have been one of the most significant hints as to the true nature of the island ever, if only we knew what it meant. In season 5 however, we get a new glimpse of the giant statue and suddenly things start to make sense.
I may be wrong, but that looks a lot like Osiris to me. Carrying the 'was', it suggests that the Egyptians believed this island to be the gateway to the realm of the dead. And why wouldn't they? With a crazy weird energy source at the center of the island somewhere.. and dead people popping up in visions, judging you.
To quote wikipedia: "Osiris was not only a merciful judge of the dead in the afterlife, but also the underworld agency that granted all life, including sprouting vegetation and the fertile flooding of the Nile River." That seems to explain that relationship between the dead people and people dieing /and/ the people who have not died even while off the island (eg: Michael).
In the underworld there were creatures called Harpies, which in the mythology, would know if you were lieing and attack you. This reminds me of the smoke monster and in many ways the ghostly incarnations that guide or sometimes attack the people on the island.
We now know the island possess bizarre time warping ability - the promise of eternal life could indeed be granted in such a place. So that's my new theory, that the Egyptians myths were an attempt to understand the island. I think we'll find that the island itself is a meta concept, beyond any one particular ideology from any one particular culture, except that every culture has some partial understanding of events that have taken place on the island in some form or fashion. After all, coming back to life is one of the oldest miracle stories around - and John Locke just did it.