There are few hard and fast rules here. Here’s some advice from our friends over at Bible Toolshed:
You may have decided that you want to read the Bible, but which Bible? There are a bewildering variety of Bible translations in English, not to mention different sizes and style of Bible even within the same translation. One good idea is to have one of the classic older translations, and a good modern translation as well. […] To some extent your choice will depend where you are already in terms of your familiarity with the Bible, and with what you hope to get out of it. If you are very unfamiliar…you might be best to get a readable modern translation like the NIV or ESV. If you are meeting and discussing with believers who regularly use a particular translation, you might find it easier to be on the same page (quite literally!) with whatever they happen to be using. If you are interested in a closer examination and study of the Bible, you will probably find it useful to have a more literal translation, if not as the basis of your studies, then at least for comparison.
A good strategy is to have the best of both worlds. Give the classic King James or Authorised Version (AV or KJV) a try, and try a modern version as well (NIV or ESV…). …
A couple of points to remember: first, it’s generally better not to go for one of the more strongly paraphrasing translations; second, no one translation has a monopoly on truth; third, whichever you choose, remember to use others for comparison, particularly when you are drawing big doctrinal conclusions; fourth, while some versions may obscure things a bit, any reputable Bible translation will help you in your understanding of God and His purpose – don’t get so hung up on the question of which translation that you never get round to actually reading the Bible!1
For anyone who wants to read the Bible seriously, it’s a good idea to have, say, a couple of different Bible translations for comparison. One idea might be to have an older translation like the KJV, RV or even the RSV, plus a more modern translation like the NIV or the ESV…. For more serious Bible reading and study you might well want to add a couple more.2
Personally, I most often read an NIV and also use an NASB (although I’ll often read and check other versions. You can do this easily on websites like Bible Gateway, Blue Letter Bible or Bible Study Tools, which have many versions available online3).
Another version that is quite popular with some of the authors here on BibleQ is the NET (New English Translation), which is available online here: net.bible.org.