The King James Version is the worlds most widely known Bible translation, using early seventeenth-century English. It is powerful majestic style has made it a literary classic, with many of its phrases and expressions embedded in our language. Even now, more than four centuries after its publication, the King James Bible remains the most famous bible translation in history and one of the most printed books ever.
NLT and NIV are very similar and are written more inline with modern English. These are often the preferred translations for most new Christians.
The NIV is the second most-read version of the Bible in United States, after the King James.
Between KJV and NKJV it is believe that NKJV will have the best of both worlds in one new Bible. They do not realize that the New King James Version is not an updated Authorized (King James) Version. Instead, the NKJV is a highly-edited new translation which is theologically and philosophically inconsistent with the AV.