The King James is the most poetic version and it is pretty accurate.  I think the ESV and NASB are slightly more accurate because they are word for work translations that are based on older copies of the Bible.  That being said, I don't think there are any major errors in the KJV.

The NLT is a paraphrase, but is probably the most accurate paraphrase.  It makes it easier to understand, but can introduce misinterpretation errors.  My son has down syndrome and so the KJV, ESV, and NASB are hard for him to understand.  The NLT  seems to be the best compromise between staying true to the original texts and being understandable for him.  Generally I refuse to use any paraphrase Bibles.