Men are not prisoners of fate, but only prisoners of their own minds. Franklin D. Roosevelt
The only real prison is fear, and the only real freedom is freedom from fear. Aung San Suu Kyi
While you are not able to serve men, how can you serve spirits [of the dead]?...While you do not know life, how can you know about death? Confucius
Do not fear death so much, but rather the inadequate life. Bertolt Brecht
As a well-spent day brings happy sleep, so life well used brings happy death. Leonardo da Vinci
Ok well I could keep going, but these quotes are sufficient.
I believe the fate worse than death in a word is, hell. I don't think it is Hell, the place we think of, but I believe it is a place or existence so horrible that it will be much worse than death.
I believe either in Book 6 or 7 we will get JKR's explination of the "after-life." There is a "heaven" waiting for the characters in her books. Nick said that there is a choice that wizards face, he was fearful of death so part of him stayed back here. He says that Sirius "...will not come back. He will have...gone on." So somewhere after the physical act of dying there is a barrier or decision that makes the leap from a ghost life to another life.
Voldemort obviously thinks of one thing, power. So the thing he fears is halt to the pursuit of that power. I think what Voldemort doesn't realise is that death is not the end. He thinks that he will be able to recover from anything and that he will always have a fighting chance, but there is a consciousness after death. For him after death will be an eternity to be trapped with no hope. He will realise that his life has been inadequate and "lifeless". Truely that would be a terrible punishment for any man.
Anywho, just some thoughts.
On slightly different note, to make a legitimate ending of Voldemort, how could he be distroyed in a way where no one would fear him coming back? I imagine it is going to have to be a very "violent" way, not simply a flash of light. Otherwise he "could" come back in everybody minds and his power over the world would remain. By violent I don't mean gory, but a death that looks like a terrible way to die.
Let me know what you think, but one thing is for sure, JKR will explain what happens after death (there was too big of a cliffhanger when Nick wouldn't answer Harry).