I don't think that your really supposed to understand Donnie Darko. I think it's the writer, or maybe Drew Barrymore, who says in the commentary that everyone is supposed to come away with their own theory. So nobodies right and no ones wrong. Your just supposed to believe in Donnie and that in a sense that the journey is the destination. That he had to understand what was going to happen before he was able to die.

All I really know is 1) I identify with Churita Waaaay to much and 2) I thought Mad World made me cry before, now I bawl. :-/