Not everyone, even in the different branches of Christianity, believes the Bible to be the complete, inerrant, verbally inspired Word of God. For example, the LDS Church believes the Bible was corrupted and had to be restored by Joseph Smith. The Jehovah's Witnesses set up their faith in agreement with their unique interpretation of the Bible, then later rewrote the Bible to agree with their unique faith.
But for most branches, and especially among protestant fundamentalist groups such as the Baptist and Pentecostals, the Bible is considered to be the sole source of authority for their teachings.
I believe that, if a book is not just the communication of a perfect being, but the complete message of a perfect God to his creation, then it must, by nature, be without error. Any errors, if discovered, would cast doubt upon the validity of the only message God has ever sent. Furthermore, such a message would not simply be internally consistent, but would be unambiguous, contain no unnecessary or irrelevant information, and would perfectly match all historical and scientific data.
It is my belief that the Christian Bible fulfills none of these criteria. Far from being unambiguous, I don't think there is a single important verse whose meaning hasn't been hotly disputed at one time or another. There is much information that appears unrelated or even detrimental to whatever "moral message" the Bible may be trying to convey. The links provided below should adequately demonstrate why.
Errancy in General:
Biblical Errancy Magazine: This magazine, edited by Dennis McKinsey, may be the most comprehensive survey of all the atrocities, misquotations, and all-around "oopsies" that exists.
A List of Biblical Contradictions, by Jim Merritt. It doesn't go into as much depth as McKinsey's site. I think the introduction is actually more useful and informative than the contradictions themselves.
Donald Morgan's Biblical Inconsistencies is a simple listing of hundreds of "mistakes." Though some are rather weak, the list as a whole is worth a look.
The Errancy Mailing List, sponsored by the Secular Web, is a great place to debate over issues of errancy. May God grant victory to those whose cause is just! ;)
Errancy of the Book of Daniel:
Farrel Till, editor of The Skeptical Review attempts to demonstrate the late authorship of the Book of Daniel by showing that while the author described 2nd century BC events with remarkable accuracy, the same author had only a vague knowledge of the history of the time Daniel was supposed to live in. There are also some related articles in the previous issues of TSR.
McDowell in the Critic's Den (Off Site): Bernard Katz refutes Josh McDowell's attempts to demonstrate the historicity of The Book of Daniel.