I see from the comments thread here that I should clarify what I meant by the "mirror image" of illiteralist fundamentalism.
Fundamentalists believe that the Bible is "literally" true. What they mean by this is that every story it contains must have actually happened in real life, exactly the way it is told. The problem is that this is not how much of the Bible was written, not how much of it is supposed to be read.
I can't figure out which way cause and effect are flowing here, but this "literal" approach to the Bible is related to the belief that scripture must be read this way, that this is somehow what it means for scripture to be "inerrant" and "infallible." For any part of the Bible to be other than "literal" would mean, from their way of thinking, that it wasn't true. If any part of the Bible is not "literally" true, then it's not infallible and inerrant, which would mean it's not scripture, which would mean, from their way of thinking, that there is no God, no purpose, no meaning in life.
For an extreme example of this approach, let's revisit our old friend Marshall Hall of FixedEarth.com. Hall, you may remember, believes in a geocentric universe in which the sun, the planets and all of the stars revolve around a fixed Earth. He believes this because he thinks this is what the scripture teaches, citing two passages on his home page. Psalm 93:1 says, "The world is firmly established; it cannot be moved." Job 26:7 says, "He spreads out the northern skies over empty space; he suspends the earth over nothing."
So based on his "literal" interpretation of these passages — one from a poem, the other from a play — Hall believes in a fixed Earth. That is the illiteralist fundamentalist position in a nutshell.
I've written before about one variety of mirror-opposites of these illiteralist believers — see "Bloody Mary Candyman" and "Freethinkers wanted" — those who I call "sectarian atheists." These are usually folks who start out like Marshall Hall, fully indoctrinated in the all-or-nothing illiteralism of American fundamentalism. They start out believing, like Hall, that the Earth must be fixed or else the Bible is false and there is no God and life is meaningless despair. And then they catch a glimpse of the moons of Jupiter or of an eclipse or of a middle-school science textbook and they realize that the Earth moves. At this point they declare themselves "atheists," yet for all their supposed rejection of their previous beliefs, they continue to share Hall's way of looking at the world. Theirs is an extremely sectarian, parochial atheism — the God in which they no longer believe is a very particular kind of God. (I don't believe in that God either, but I am not an atheist.)
In addition to these sectarian atheists, there's another group of folks who tend to function like the mirror opposites of the illiteralist fundies. Many of these folks seem to be journalists — the one's who always seem to be interviewing people like Marshall Hall or Tim LaHaye, uncritically accepting their claims to be representative of what Christians believe. Thus we get article after article on the Left Behind books glibly reporting that the book is a fictional account of events described in the book of Revelation. The failure of these reporters is simply a matter of laziness — they don't know what the Bible actually says, or what most Christians actually believe, so they accept whatever Hall and LaHaye tell them.
Both the lazy reporters and the sectarian atheists tend to hold similar beliefs, based on the same reasoning, as the illiteralist fundies. All three groups believe things like:
If there was not an actual, flesh-and-blood man named Noah who actually, historically built an ark when he was actually 700 years old before a flood that actually covered the entire surface of the planet, then God is bunk.
If there was not an actual, flesh-and-blood man named Jonah who actually spent three days inside the belly of a giant fish in the Mediterranean, then all religious belief is foolishness.
Proof that the world is more than 6,000 years old is proof that God does not exist.
I grew up surrounded by fundamentalists who made such claims. It's still somewhat jarring to me when I encounter non-fundies who accept their logic, if not their conclusions.