For any thinking Christian (or any Christian with compassion), an eternal hell is probably the hardest doctrine to accept. As I said below, it was the question that really started me on my journey toward atheism. Here's an article about a pastor who's leaving a megachurch to further promote his book, Love Wins (and, one guesses, because his message is not striking a chord at his church). The article says that "he wrote the book because the Christian message that God is love seems to have gotten lost."
Understandable. It's hard to reconcile "for God so loved the world that he gave his only son" with "believe, or fry in eternity!" Universalism makes Christianity a whole lot more palatable, frankly. But some of the reviews on Amazon point out the obvious (which my daughter pointed out to me)-- it's Jesus who said we go to hell if we don't accept him. If you have a problem with that concept, then you have a problem with Jesus.