It wasn't until I was in college (or thereabouts) that I learned of an original ending that wasn't used. I've always wanted to see it, hearing that it dealt with worldwide annihilation. I never bought the DVD, holding out for the super deluxe edition (come on Criterion!) with the original ending. Not the happy, piece of shit that exists now (actually, the ending is very satisfying as it stands). As luck would have it, IFC.com just put out a small list of movies that had the endings tampered with by studios and it directed me to the following series of videos of the original Little Shop of Horros ending! With commentary from Frank Oz!
I almost can't believe the studio didn't use this stuff because it looks amazing and must have cost a fortune. Oz gives a fair amount of interesting info about what it took to operate Audrey II, as well. Enjoy!