Of course, the broader question in the area of inerrancy is not how many inconsistancies we can find (i.e. differences in the Gospel accounts), or if God really did commit genocide, but rather what is the message that is being presented to us? The Bible tells us a story. A story that speaks of the relationship between God and man.
Whether you believe in a literal Creation account or evolution, it doesn’t have much bearing on the fact that the story of the Fall tells about the schism in the relationship between man and God. You don’t have to be a literalist to see that. The story goes that God made man (whether through special creation or evolution) to commune with and interact with that creation. And somewhere along the way, that relationship got tarnished. And I can pick that up even if I see the story as allegorical. The Tree of Knowledge of Good and Evil represents our selfish-interest, because of the Law attached to it. All things were permissable for the man and woman to enjoy, except when man placed something ahead of his relationship with God (in this case, represented by the Forbidden Fruit - the lust of the eyes, the lust of the flesh, and the pride of life apart from God). The Tree of the Knowledge of Good and Evil represents the Law, for it is something that 1) God does not wish for us and is an established boundary for our good and 2) cannot be kept anyway for we cannot sustain ourselves without the life of God. The Tree of Life represents Grace, that is only found if the life of Christ; the life of God, which CAN sustain us, through the operation of the Holy Spirit as we yield to Him. It is about living the life of God in us apart from the Law, yet by faith fulfilling the Law through Grace.
I can believe in evolution and still bring that concept to light, even if there were no literal Adam and Eve. In a way, we are our own Adam and Eve, rebelling against God with our own selfish-interest. We died to God in our selfish-interests.
Revelation, then, must be consistent throughout scripture that conveys the first concepts of the relationship between God and man, and the remedy for reconciliation. If that is the basic truth that needs to be conveyed, then the Scriptures have accomplished that. That message is consistent all the way through.
On the other hand, we must also be careful of how much we would consider allegory, for if we conclude that the story of Jesus is allegorical, then nothing matters anyway if Christ isn’t risen indeed. The truth of the matter is that Chrisianity is a historically-driven faith. So just how much are we willing to believe, yet retain enough of historical truth to sustain our faith?