For Bible studies, I have several standard paper based versions at my disposal,
mainly KJV, NKJV, NASB95, and ESV. I have other paper versions but do not use them
for study. Besides the main sources, the Holy Bibles, I use a few different
commentaries, dictionaries, and concordances.
However, I have found it more efficient to use computer based Bible study software.
I am using one software package as my main study aide - eSword.
The eSword program is free (donations welcome) and comes with a few useful resources. You can download additional versions of the Bible, commentaries, dictionaries, devotions, graphics, and reference books. They list many free book downloads. The dated program interface contains many features similar to higher priced software. In addition, the older look is good because it results in the software performing tasks much faster than more expensive packages.
I also will occasionally use my free Kindle application on my tablet when not at home. There are also many good commentaries available through the Amazon website.
I do still enjoy reading the Bible using the paper versions. However, you cannot beat the computer's ease and speed when looking up information, searching the dictionaries and referring to concordances.