The four English translations used most widely by evangelical Christians are the King James Version (KJV), The New King James Version (NKJV), the New International Version (NIV), and the New American Standard Bible (NASB).
The KJV is the oldest of the four and continues to be the favorite of many. It is known as the Authorized Version of 1611 because King James I approved the project to create an authoritative English Bible. Although it contains many obsolete words (some of which have changed in meaning), many people appreciate its dignity and majesty. The NKJV is a similar translation, taken from the same group of ancient manuscripts, that simply updates the archaic language of the KJV.
The NIV was completed in 1978. Its translators did not attempt to translate strictly word for word, but aimed more for equivalent ideas. As a result, the NIV does not follow the exact wording of the original Greek and Hebrew texts as closely as the KJV and NASB versions do. Nevertheless, it can be considered a faithful translation of the original texts, and its lucid readability makes it quite popular, especially for devotional reading.
The NASB, completed in 1971, is a revision of the American Standard Version of 1901. It is a literal translation from the Hebrew and Greek languages, making it a favorite for serious Bible study.
Which version is the best to use? Ultimately, that choice needs to made by each person individually. Each of the versions have strengths and weaknesses, but they are all reliable translations of the Bible.
Ideally, the serious student of Scripture should become familiar enough with concordances and word-study aids, so that even without a thorough knowledge of the original languages, he or she can explore some of the nuances of meaning that arise out of the original texts.