I've made it no secret around here that I question the common understanding of Hell being a literal, consuming fire that torments a conscious soul day and night without end. I do believe in Hell, and a "fire" of Hell, but I've found it curious that many believers accept a metaphorical representation of Heaven (e.g. streets of gold) as represented in Scripture, but reject a similar metaphorical representation of Hell.
In The Reason For God Tim Keller summarizes my current thinking on Hell:
In short, hell is simply one's freely chosen identity apart from God on a trajectory into infinity. We see this process "writ small" in addictions to drugs, alcohol, gambling, and pornography. First, there is a disintegration, because as time goes on you need more and more of the addictive substance to get an equal kick, which leads to less and less satisfaction. Second, there is an isolation, as increasingly you blame others and circumstances in order to justify your behavior. . . . When you lose all humility you are out of touch with reality. No one ever asks to leave hell. The very idea of heaven seems to them a sham.
The idea of Hell being something of a choice for the damned fits hand-in-glove with the idea represented by C. S. Lewis who said that the damned souls are in some sense successful rebels to the end, and, as Lewis' character George MacDonald says in The Great Divorce, "There are two types of people in the world. Those who say to God, 'Thy will be done,' and those to whom God says, in the end, 'Thy will be done.'"
I believe Dallas Willard presents a similar picture of Hell in Renovation of the Heart.
I'll end with another Keller quotation from the aforementioned book:
All God does in the end with people is give them what they most want, including freedom from himself. What could be more fair than that?