What Bible translation does John Piper recommend?
From Gospel Translations
There are two main translations today which John Piper and DG would recommend: the NASB and the ESV. Both of these translations seek to capture as fully as possible the precise wording of the original Greek, Hebrew, and Aramaic texts. In contrast, many translations today follow a "thought-for-thought" philosophy, which inevitably sacrifices a greater degree of accuracy and meaning for the sake of textual simplicity.
While thought-for-thought translations do result in a high level of readability, we believe that the expense they pay in decreased accuracy is too high. Many interpretive decisions that should be made by the reader are instead already made for the reader by the translator. The sense of the original is often conveyed less fully than would be the case in a word-for-word translation, and many important nuances and contours of the original are lost.
Further, the NASB and ESV have accomplished a solid degree of readability and literary excellence in conjunction with their more precise adherence to the originals. The ESV especially stands out in this regard. It seems to uphold the precision and accuracy of the NASB while achieving an even greater degree of clarity of expression.
You can read more on the translation philosophy of the ESV at the Web site of its publisher, Crossway Books
You can read more on the translation philosophy of the NASB at the Web site of its publisher, The Lockman Foundation