How did you interpret the ending of The Box?

I interpret The Box's ending to represent Arthur's salvation. Arthur was given the choice to live freely with a hot wife, a million dollars, a son (albeit disabled), and the chance to have more children, but instead he chose to live with the burden of killing his hot wife, imprisonment by men in black, and separation from his revived son Walter. Quite a sacrifice so that Walter would have an acceptable future! I believe that "those who control the lightning" view Arthur and Norma as representatives of the average nuclear family, so that Arthur's final decision carries weight in "their" overall opinion of humanity. How he arrived at that decision is a more involved question...

I've been pondering the scene with the three water-gates, presented to us when Arlington's wife says "one leads to salvation, two lead to damnation." At first I thought this quote referred to a single gate being somehow different from the rest. However, I am beginning to think that director Richard Kelly would never leave the plot to luck, so now I believe that all the gates were the same and the statement "one leads to salvation, two lead to damnation" was really a clue to Arthur about his NEXT CHOICE between saving Norma or Walter, NOT about his choice between the water-gates. Arlington's wife used a metaphor! Her statement probably means "one person will lead an acceptable life, or two people will lead an evil life." As you know, Arthur chose for Walter (one person) to lead an acceptable life, rather than for he and Norma (two people) to have a million dollars and forsake Walter... so his choice of one person led to salvation. I realize the metaphor might sound far-fetched, but anything goes in this type of film!