One of Annihilationism's better arguments is that there are several biblical images that portray the final state as one of complete harmony: God has reconciled all thing to himself, he rules over all, etc. Hell must ulimately be empty then, otherwise there are people who are not in complete harmony with God.
The standard counterargument against it is the lake of fire into which are thrown the Anti-Christ, the beast, and death who will suffer for ever and ever. When confronted with this, annihilationists generally point out that there are no people suffering for ever and ever, just these other things (usually taken to be systemic sin structures). When it is pointed out that people are indeed thrown into this lake of fire, they point out that it was intended for the Anti-Christ et al. and not for people. So though it may torture those things forever, it may easily consume a person (the same way that a punihsment designed for an adult might kill a small child).
Now, each part of that parry is fine by itself. But together it doesn't work at all. By conceding that the lake of fire punishes the Anti-Christ et al for all eternity, annihilationists can no longer claim the Complete Harmony argument, since the Anti-Christ et al are hardly in harmony in the final state.
Weirdly, I've only read one paper that calls the annihilationists on this count. Everyone else seems to let them get away with it. I have yet another compromise position that I use to wiggle my way out, but I've yet to see a good annihilationist defense of this point.
Traditionalists typically just assert that hell is harmonious with heaven, even if we don't understand how. All actual explanations of how this is so have seemed pretty weak to me.
How do you guys deal with the Complete Harmony argument?