Couple of things first off.
1) Is there any way, any where, to download the, "Am I Dead?" clip? Not the audio, but the visual as well.
2) Concerning the life that must be exchanged for Clarks, isn't it possible (sorry if this has been said) that Jor-El is going to give up his own life force in self-sacrifice for his own son?
Listen to that clip of Jor-el/Lionel talking to Clark again, and listen to the pain in his own voice. Jor-El might have finally done the one thing that will prove he trully is a good guy by sacrificing himself for his own son's life, instead of just taking the life of someone else. Nothing else could better show viewers just how much Jor-El really loves his son than this act.
Jor-El isn't floating about in the movies any more is he? Nope, all Clark has left are his holograms. Listen to Jor-El's last words to Clark as well. "Always know..that I love you." There's real pain in that voice, the same you would expect a parent to express to their child when they know they don't have much longer left with them.
It would probably crush Clark to realize his biological father would end his own existance because of the love for his son. Clark would lose his last real tie to his heritage, and it would be his fault, but seeing the self-sacrifice of his father would be a deeply painful reminder of his responsibility to the world, and would also teach him about the power of self sacrifice as well.
In the end, the only way Clark will know his father will be through the holograms at the FoS, and it was only through his own selfish decision that he is no longer able to speak directly with his father anymore.
Very sad, and extremely powerful stuff, me thinks.