This is probably wrong and completely irrelevant to the story, but does anyone think that Sarah (Jack's wife) could actually be Ben's friend Annie?
The fact that Ben kept the carving Annie gave him suggests that they were possibly in a relationship. Ben also attempts to court Juliet when she first arrives on the island.
In season 3 Ben suggsts to Jack that Juliet has a 'striking resemblance' to Sarah. Maybe the reason Ben is so interested in Juliet is that she reminds him of Annie/Sarah- which would explain his comment to Jack (personally, I could never understand it, because I reckon they look completely different).