Actually, the NIV is a literal translation, not a thought-for-thought translation. It is one of the more "modern" translations, as opposed to the King James Version (a.k.a. Authorized Version of 1611). Newer translations such as NIV and NASB use different manuscripts for translations than the KJV. In general, there are 4 general "text-types" of manuscripts that are used to translate the Bible. They are the Alexandrian text-type (predominant around Alexandria, found in most papyri), the Western text-type (mostly the western area of the Roman Empire), the Byzantine text-type (found in most later uncial and miniscule manuscripts, mostly from the area around Constantinople aka Byzantium) and the Caersarean text-type (which seems, to me anyway, to be the least common one and it's disputed by some scholars). Anyway, the KJV draws almost entirely from the Byzantine text-type, which is considered the "fuller" text-type, while newer versions draw a lot from the Alexandrian text-type, which is considered more "concise." (Modern versions don't just draw from the Alexandrian text-type, though... rather, they seem to be a blend of them all). There is actually a lot of controversy sometimes, because there are many KJV-only advocates who say that the modern versions such as the NIV eliminated important verses to become more concise, to take away from the deity of Christ, etc. (I have met some people like this at a Baptist church that thought the only "true" Bible was the KJV... but most Baptist churches are not like that, at least not in my experience). Anyway, the minority of scholars believe that there was some conspiracy on the part of the modern version's translators to eliminate verses. That's not a popular opinion. Most scholars agree that the Alexandrian text-type is actually the oldest, and that the stuff that makes the Byzantine text-type (used in the KJV) "fuller" was actually added later on. A lot of these verses were probably added in error later on by scribes... being a scribe was a very difficult, very time-consuming job, and it often took place under some pretty hot or pretty cold, pretty cramped, conditions. Sometimes, especially after working awhile, the scribes would add things in because they were used to hearing phrases in the church and they would assume that that's how the phrase should be read. Sometimes scribes would translate things differently because they think what they heard somewhere else was better, or they think that, since the church used a specific phrase so much, it must have been left out accidentally so they would add it in, even though it originally wasn't there. These difference, though, don't make a different Bible... they don't change any important doctrines, etc. I just find this topic so fascinating, and when I read the question, I was very excited!
