I'll fill in the spoilery blanks for you now -- rumors were that test audiences were quite appalled that Hugh Jackman's character, The Drover, died at the end of the film. Fox was certain that Jackman's tragic end spelled doom for the box office, but Luhrmann brushes off the rumors, calling them "naive" and "profoundly misinformed." He also points out that Fox would hardly have taken issue with The Drover's death, since they happily froze Leonardo DiCaprio in Titanic, and we all know how that box office turned out.
It turns out, he filmed three different endings and tested two -- one where Jackman lived, and one where he died. Audience reactions were the same for both endings, but he decided to choose the third, which remains a mystery to all but him and his cast. "There was always a struggle within me," he said. "There's the way Titanic ends and there's the way Gone With The Wind ends. It's neither of those. It's an ending specific to this moment and it's what I want the film to give out and what I need in my own life. It's what I want to feel. On that level, it's completely personal."
So, now you have it -- Luhrmann is firmly in control, we'll be delightfully surprised by the ending, and I may not have to watch The Drover die. Good news all around! (We won't talk about the fact that its reportedly still not done ...)