Thanks for your question.
My personal preference is for the King James Bible. However, this translation is not the only useful translation. In fact the language of the King James is very challenging to many. It has a Shakespearian turn of phrase which many folks find difficult to follow.
Of the modern translations, the 1971 RSV (Revised Standard Version) is probably the best although the NKJV seems to be very good too. Many prefer the ESV (English Standard Version). It has a solid reputation among scholars and lay people alike. I personally use the KJV for my own reading and meditation but for study I use the interlinear AV/RV (the AV is another term for the KJV) published by Cambridge University press. Their centre-references and marginal notes are second to none and the RV alternative renderings often clear up difficulties with the King James Version's use of language.
There are problems of language with the KJV. In fact, I have a book called "The King James Bible Word Book." This book is over 400 pages in length detailing words used in the KJV that have changed their meaning since that translation was first published in 1610. For example, in Psalm 119:47, the Psalmist says (KJV) "I prevented the dawning of the morning." The modern reader is a bit mystified by his meaning. That's because the word "prevent" has changed its meaning in English. In the days of the translators of the KJV, "prevent" meant "to go before, anticipate, or precede." The RSV correctly translates this verse "I rise before dawn." The point is that the KJV, although an excellent translation, has its problems in language and there are some outright mistranslations too. But this could be said of almost any version. That's why it helps in study to use different translations and to be aware of their strengths and weaknesses.
Some folks have raised the use of the KJV to level of doctrinal significance. This is not wise. If we do this we sink to the level of the Jehovah's Witnesses who will sanction only one version of the Bible, their "New World" translation.
The King James Version is only a translation of God's word. Indeed, if we want to read the original manuscripts, we will need to become conversant with Hebrew and Greek! The point is that it is a translation, in magnificent language, suitable to the translators' day and generation and indeed it has served many generations following. But as time passes, language changes. The challenge to the translators is to present the living and abiding Word of God in language that is true to the original Hebrew and Greek manuscripts and, at the same time, maintain the dignity and power of its wording. Just as the King James translators and those who went before them such as Wycliffe and Tyndale rescued the Word of God from the archaic Latin and Greek of the colleges and monasteries and presented it in the language of the people of their day, so modern translations are attempting to convey, in modern language, the living Word of God in all its power and dignity being true to the actual original manuscripts. Some have succeeded better than others. The Word of God is inspired but, alas, the translators are not. If you want to read a very thorough and sympathetic account of the translation of the King James Bible, I would advise you to read, "God's Secretaries - The Making of the King James Bible" a book by Adam Nicolson and published in 2003 by Perennial, a division of Harper Collins Books. You should be able to find it in any decent bookstore. It accurately portrays the idealism and the not so savoury pride, ambition, and political maneuverings which attended the translation of the KJV. The KJV is a magnificent translation and for those of us who appreciate the grandeur of its language, and who are aware of its shortcomings, it is second to none. However, it is not the last word in translations.
I hope you have found this helpful.