I've been reading Helmut Thielicke's systematic theology The Evangelical Faith (BTW, you can get the whole set for about 6-8 bucks on Abe or Amazon- it's really cheap). Any how, he's spending most the first volume dealing with the modern theology of consciousness (he calls it "Cartesian theology") and also the claim on the part of folks like Bultmann that the Bible is mythological. He deals with this claim in a number of way (he mostly does a good job, I won't go into all the details), but his best argument is that the Bible is not mythological, but the end of mythology.
One of the major problems with claiming that the Bible is mythological, is that a "mythological" worldview is somewhat difficult to define. Mainly when Bultmann and others in the mid-20th century used the term, they meant beliefs people had prior to the 20th century that didn't fit all that well into the boring, naturalistic, scientistic view of the world held by Marx, Freud, and Darwin. Thielicke correctly points out that a better definition of the mythological is a view of the world where reality is composed of a concert of personified powers (the "gods" perhaps) that compete with one another for power. In this worldview, there really is no transcendent horizon of existence because there is no creation ex nihillo. Hence, everything is cyclical. The eternal stuff of the world inevitably recycles itself. There are only so many possibilities for this recycling. Hence, reality will necessarily repeats itself over and over again.
The world one finds in the Bible is actually quite different and therefore not mythological. When one reads Genesis 1, the first thing to notice is how empty creation is. In other words, there are no gods, ancestral spirits, woodland spirits, or Jinn one might find inhabiting the world of the earlier cultures. Moreover, since God pre-exists creation and calls it out of nothing, God is not a being among beings. He therefore is free from the competition of the gods that one finds in the mythological worldview. Being infinitely free, he does not fear human freedom and therefore he can give humans their freedom by his word of grace. Lastly, the cyclical view of history is broken by the doctrine of creation ex nihillo. A God who calls all things into existence out of nothing, can very well create again. Human being therefore are not trapped in an endless cycle, but can trust in God new eschatological possibilities. There need be no continuity between their earthly efforts under the law and God's new possibilities of grace given from without.
A couple of things are clear from this comparison. First, it's obvious that for most human beings (under the power of the law and the compulsion of self-justification) the mythological view of the world is actually much more appealing. If the gods are beings among beings, they can be manipulated (magic and sacrifices). Nevertheless, as Thielicke points out though, it is also a deeply enslaving view of the world. Human beings must endlessly self-justify, but without the end of the law and the possibility of new creation it will ultimately be a sisyphusian struggle. Our best attributes and efforts will inevitably fail, die, be reborn, and fail again.
The second thing to note is that contrary to popular opinion, the modern view of the world is actually quite mythological. Though Christian civilization has definitely left its mark on western consciousness (unlike the Japanese, our world is empty of gods and spirits), materialism lends itself well to a mythology. Whereas the ancient world had gods and spirits that could be manipulated, modern people prefer to talk about the "laws of nature." These laws can never be broken by something like a miracle. Though there is little logic to this position if one believes in an almighty God, even religious persons in the modern world often discount the possibility of miracles. Why? In order that they might be able to control these quasi-personified powers of natural law. Instead of magic and sacrifice, modern humans try to manipulate their gods through technology. Of course, this cycle of manipulation is also unending as well, just as the modern quest for autonomy and self-assertion is also unending. There can only be endless recycling and an eternal return (as Nietzsche rightly points out) because there is nothing but eternal matter reconfiguring itself.