There was an interesting programme on the BBC this week about books and it featured the codex Sinaiticus from the fourth century, which it described as the oldest surviving complete Bible.
It said that one of remarkable things about this manuscript is just how many alterations had been made in the text, over 20,000, which is a considerable number on every page, and far more than could be explained by scribal errors. The programme said that this indicated the instability of the text of the Bible even at that early stage, and contributed to doubts about the inspiration of the scripture in the nineteenth century when the manuscript was found.
http://www.bbc.co.uk/iplayer/episode/b00ydj1m/The_Beauty_of_Books_Ancient_Bibles/
PSacramento when you say Ehrman's scholarship does not compare favourably with Metzger, have you read much of Ehrman's work before he started writing popular books for a general readership? His books on the text of the Fourth Gospel used by Origen and the text of the gospels used by Didymus the Blind are pretty detailed and his book The Orthodox Corruption of Scripture stands somewhere in the middle between his popular and scholarly works.
I think it is very interesting that Metzger, who was at one time viewed as a conservative scholar, chose to collaborate with Ehrman on the final edition of one of his most important books The Text of the New Testament: It's Transmission, Corruption and Restoration. Metzger certainly developed his views considerably from his younger days when he was defending the authorship of the book of Daniel for example.