I've posted a few theories lately that people seem to enjoy. Let me know if this one could make sense.
A lot of people were wondering why the candidates back in time were sent back to the present day when Jughead went off. I believe Jughead was merely the reason for the fertility problems and healing properties of the island (see my other blog for that).
I don't think Jughead or its detonation had anything to do with that final time leap. I was watching "this place is death," when MiB (disguised as Christian Shephard) tells Locke it was HIM, and not Ben, who was supposed to turn the wheel. I think that as Locke is lowering himself down the well towards the wheel, when the time flash occurs and he falls and breaks his leg, I believe that Locke was flashed to the point in time RIGHT before the candidates are returned to present day. As if the whole conversation between Christian and Locke is happening at the same time as the "incident," so as Locke turns the wheel, Juliet detonates Jughead.
therefore, I think it's really Locke and the donkey wheel (and the scene in the episode "this place is death") that sent the candidates through their final time flash (as seen at the beginning of "LA X pt 1" of Season 6).
Does anyone agree or think otherwise? I'd like to hear your ideas.