There are a few things everyone seems to have forgotten about.
Firstly, end of season 1 – the thing that drags locke down and makes the weird noise.
Secondly, What are the voices in the trees?
And in the second season what is that black clould thing that floats in front of echo?
Whats the crack with walt when he was talking to Shanon?
Why have all the stations been abandoned?
Whats in the other stations on the map?
My theory is the island is a place beween heaven and hell for the lost people to be tested. Echo knows this i think. The button tests their faith.