In yet another argument undermining the wisdom of the New York Times' paywall, Ross Douthat, resident prude, argues that hell must exist.  His argument hinges on the reality of human choices.  Human choices, without the possibility of eternal damnation, just wouldn't be real.  He writes:

Doing away with hell, then, is a natural way for pastors and theologians to make their God seem more humane. The problem is that this move also threatens to make human life less fully human.

Atheists have license to scoff at damnation, but to believe in God and not in hell is ultimately to disbelieve in the reality of human choices. If there’s no possibility of saying no to paradise then none of our no’s have any real meaning either. They’re like home runs or strikeouts in a children’s game where nobody’s keeping score.

In this sense, a doctrine of universal salvation turns out to be as deterministic as the more strident forms of scientific materialism. Instead of making us prisoners of our glands and genes, it makes us prisoners of God himself. We can check out any time we want, but we can never really leave.

The doctrine of hell, by contrast, assumes that our choices are real, and, indeed, that we are the choices that we make. The miser can become his greed, the murderer can lose himself inside his violence, and their freedom to turn and be forgiven is inseparable from their freedom not to do so.

As Anthony Esolen writes, in the introduction to his translation of Dante’s “Inferno,” the idea of hell is crucial to Western humanism. It’s a way of asserting that “things have meaning” — that earthly life is more than just a series of unimportant events, and that “the use of one man’s free will, at one moment, can mean life or death … salvation or damnation.”

There are other ways our choices are real, I'd argue.  In the first place, our choices create our character right now.  Our choices also affect other people right now.  That, I think, is probably punishment enough.  Meditating on eternal damnation before deciding whether you want to have carnal knowledge of chunky Reese Witherspoon seems a bit much.

Not to be facile, but Douthat also seems to offer one key reason for not thinking there's a hell:

Is Gandhi in hell? It’s a question that should puncture religious chauvinism and unsettle fundamentalists of every stripe. But there’s a question that should be asked in turn: Is Tony Soprano really in heaven?

Seems like if there were a hell, and if there were a just overseer of it, we'd have an absolutely unequivocal answer to this question.  Turns out, however, we don't.  So maybe our choices have eternal reality in hell, which just can't determine which ones will send us there.