Personally i use a few different translations when doing a deep study. My favorite is the NKJV Geneva study Bible. I also use the NIV, KJV, PHILLIPS, ESV and NLT. Reason? While not taking away from the content or meaning some word a verse just a little different so i can understand it better. Also when looking at the study notes some will go into greater depth for bettet study.
But, it comes down to preference. Which is easiest for you to read and undetstand. As long as the Word of God is correctly translated in the Bible you use then, for me, i dont feel there is a good, better, best.
As someone noted before...stay away from the New World Translation as it is incorrectly translated. Because of that they change certain words thus distorting the actual meaning and changing it theologically (study of God).
I would also not use a "paraphrase" Bible as my main Bible either.
Pray before study and you will be fine no matter which translation you use.
Psalm 25 4,5 "Show me your ways, O Lord, teach me your paths; guide me in your truth and teach me, for you are God my Savior, and my hope is in you all day long".
Psalm 32:8 "I will instruct you and teach you in the way you should go; I will councel you and watch over you".
Proverbs 3:5,6 "Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge Him, and He will make your paths straight".