Question: "Why are there so many Bible translations / versions, and which is the best?"
Answer: The fact that there are so many Bible versions is both a blessing and a problem. It is a blessing in that the Word of God is available to anyone who needs it in an easy-to-understand, accurate translation. It is a problem in that the different versions can create controversy and problems in Bible studies, teaching situations, etc. The differences between the translations can also be a subject of great division within the church body.
It is probably wise to have access to at least 2 or 3 of the major translations (KJV (King James Version), NIV (New International Version), NAS (New American Standard), NKJV (New King James Version), NLT (New Living Translation), for comparison's sake. If a verse or passage in one translation is a little confusing, it can be helpful to compare it side-by-side with another version. It is difficult to say which translation is the "best." "Best" would be determined by a combination of the translation method personally considered best and your interpretation of the textual data underlying your translation. For example, the KJV and NAS attempted to take the underlying Hebrew and Greek words and translate them into the closest corresponding English words as possible (word for word), while the NIV and NLT attempted to take the original thought that was being presented in Greek and Hebrew and then express that thought in English (thought for thought). Many of the other translations attempt to "meet in the middle" between those two methods. Paraphrases such as The Message or The Living Bible can be used to gain a different perspective on the meaning of a verse, but they should not be used as a primary Bible translation.
There are many more Bible versions out there. It is wise to have a personal method for determining whether a particular Bible translation is accurate. A good technique is to have a set of Scripture verses you know well, and look those verses up in a translation you are unsure of. A good idea is to look at some of the most common verses which speak of the deity of Christ (John 1:1, 14; 8:58; 10:30; Titus 2:13) to make sure a Bible version is true to the Word of God. We can be confident that God's Word is truth, and that it will accomplish His purposes (Isaiah 55:11; 2 Timothy 3:16-17; Hebrews 4:12).