First of all, if I had to choose reading my Bible or reading good theology books, I would choose to read my Bible and burn all of my books (but I don't think most of us have to make that choice) . Also, I don't think most people should read a lot of books, but they should master and know a few good books well. Please hear the advice of Martin Luther, the great reformer:
"A student who does not want his labor wasted must so read and reread some good writer that the author is changed, as it were, into his flesh and blood. For a great variety of reading confuses and does not teach. It makes the student like a man who dwells everywhere and, therefore, nowhere in particular. Just as we do not daily enjoy the society of every one of our friends but only that of a chosen few, so it should also be in our studying. The number of theological books should ... be reduced, and a selection should be made of the best of them; for many books do not make men learned, nor does much reading. But reading something good, and reading it frequently, however little it may be, is the practice that makes men learned in the Scripture and makes them pious besides." (thanks for the quote Geoff)
Well 4 years ago, 98% of all my reading consist of accounting books, sports magazines and newspapers. But then I met John Piper (see my debt to Piper at http://fpcinhouston.org/forum/viewtopic.php?t=193), who challenged me (and still does) in all the areas of my life. And one of Piper's challenges, is that if I wanted to make an impact or a difference in my life and others, I needed to know my Bible better, and one of the ways to do so was to read good books.
So why should you know your Bible Better? (just a few)
1. Knowing my Bible better allows me to know better the beauty and glory of the one and only living God and his son, Jesus Christ.
2. Seeing the glory of God through Christ (which we see in the Bible) produces sanctification, that is it produces holiness.
3. The Bible teaches how to love God and people by giving me principles.
4. The Bible teaches me the methods and priorities of the church, and defines the church
So why read "good" books?
Basically, I read good because most of the times I just don't understand the Bible and I need help from the universal church, both past and present, to teach me.
I just finished reading Dr. Moore's book "The Kingdom of Christ" and it taught and reminded me that "salvation" or "redemption" is broader than just individual forgiveness of sins and people going to this spiritual realm called "heaven", but "salvation/redemption" has a community aspect to it, and it's larger than just forgiveness of sins, that is, it consist of being progressively "saved" from sin through the Spirit (sanctification) and it involves the "redeeming" of a physical world, (not through violence,but sacrificial love of the church), in which the completion of "salvation/redemption" of both people, church, and the physical world happen when Christ comes back in his second coming to consummate his kingdom.
Therefore I believe if the church had a larger biblically vision of "salvation/redemption", we would act differently, that is we would have more concern for the physical realm, the community, the day to day fight of sin (sanctification), and etc....that's why I read good books.