The problem that is endemic to this question is that there is no one-sentence answer available, insofar as one can say, this or that translation is the best there is. When approaching this question we must ask ourselves whether we want:
1 A Bible that conveys as literally as possible the original language syntax so that I can see the text behind the translation
2. A translation that is readable in a modern day English idiom that conveys the flavour of what it meant to the original readers.
3. A translation that reflects the piety inherent in something that is holy.
4. A translation that does not evaluate its textual probity from a translator's pre-conceived bias.
There is no single translation that fulfills all four requirements even remotely, and that is the challenge, both for the craft of the translator, and the disposition of the reader. A translation that is more literal than periphrastic is wooden and defies easy reading. A translation that is "understandable" becomes indefinable as a clear reflection of the original.
There is a sense in which every translation can be accused of being a product of a translator's "bias". For instance, if I translate Jo 1:1c as "The Word was God", am I reflecting the original [because that is what it says] or am I being biased by Trinitarian leanings [because one may argue that this not what it means]. If I translate Acts 20:28 "The Church of God which He purchased with His own blood" am I being Trinitarian in my bias, or am I being Unitarian biased if I say, "The Church of God which He purchased with the blood of His own [Son]"?
If I transliterate the word "Hades" rather than translate it, am I being faithful to my function as a translator? Hades is in fact a personal name of the Greek God of the Underworld, so am I being "understandable" or ambiguous? What will the reader be left with? Am I reflecting some pagan mythical infusion into Christian protocol? Will the reader "understand" what I am translating? A single minded reader, reared in the closed conduit of Watchtower learning may have no difficulty, but then this supposes that one is translating the Bible merely for the purpose of reinforcing a pre-conceived doctrinal imperative.
If I were indeed to translate "Hades" into an English equivalent, what should I say? "Abode of the dead"? "The Underworld"? "The place where the dead are consigned"? If I do this, I have on the one hand made, what I believe the Bible is saying, clear, but if I am suggesting to a non receptive reader such as a Watchtower follower that this implies some form of life after death, then I will be accused of a translator's bias.
Thus one needs to be realistic, and accept the impossibility of attaining to the "most perfect" translation of the Bible. Does this mean that there is no answer? Not really. The best one can do is to invest in what is called a "Study Bible". There are several on the market today which reflect various scholastic opinions, from the Harper Collins NRSV Study Bible which incorporates extreme liberalism, while on the other hand The NASV is the product of the best conservative learning. And there are several in between. [ESV Study Bible, NLT Study Bible, HCSB Study Bible, NKJV Study Bible, NIV Study Bible etc] The Jewish Study bible is unique in that it provides several critical OT passages with a Jewish perspective [Ex Isa 9:6]
These translations incorporate several footnotes which attempt to unravel the intricacies of the original. Probably the best Study Bible available today is free and available for download at the www.bible.org web site. The NET Bile that they produce has more than 80,000 footnotes on several passages that may cause difficulty.
Then there are devotional Study Bibles that help one to see that one is not indulging simply in an intellectual pursuit, but that one is approaching something that is Holy. The are various "Life Application" Study Bibles, [ESV, NKJV, NIV etc] as well as "Spirit Filled" Study Bible [same as before].
Cheers