If I had to die for a cause it would be cultural immortality.
In other words: If I had to die for something, It would either be while committing the greatest atrocity known to mankind, or the greatest act of goodness known to man, so that I will be remembered.
I don't particularly care which one.
If I were to name someone who succeeded and achieved this immortality I'd say Hitler. (did I just invoke Godwins law? I think I didn't). Sure he is pretty much considered the most evil man who walked the earth, but people remember him.
I can sadly, not mention someone on the other end of the spectrum who succeeded on the same magnitude that Hitler did (who was not a cultist and a religious figurehead, and therefore does not count), on the other hand I'd rather be remembered by facts than fiction.
But truth to be told, I'm probably too much of a nice guy to ever "pull the trigger" so to speak, and besides; no cause will be good to me if I'm dead, except that one. Mortality is something you cannot escape, but obscurity however, can be.