Last Seasons Finale

The show and the writers tried to show us a glimpse of the future in last year's season finale.  Does this put a damper on all the purgatory theories?  Personally, I still think purgatory is the best theory for the Lost crew.  And the added information from the helicopter pilot just makes this theory seem a little bit stronger.

I know there are tons of theories out there, but what else is there…that really makes sense?