I recently heard of someone who made a mistake in his ministry. His mistake was to write down the title of a book for someone he was discipling to go and read. The book was written by an author from a very different stream of christianity. The content of the book was solid, nonetheless, he was run out of the church essentially as a false teacher.
I remember reading an article several years ago about the concept of a liberal education. At one level the concept of “liberal” refers to the wide and free reading across the spectrum. It’s ironic that today many of the liberal seminaries will never include “conservative” books on reading lists, yet conservative seminaries recommend and even require the reading of “liberal” scholars. Which is truly liberal? I went to two liberal seminaries, that is, ones which encouraged reading from all over the spectrum (please don’t misquote this sentence – I really went to two very solid and conservative seminaries, for which I am genuinely grateful!)
So let us read widely. Others may not appreciate the value of this practice, but they don’t have to know about it. It is not possible to have genuine conviction without the testing of our ideas. We can only test our thinking by reading outside of our own theological camps, whatever they might be. So read widely, but disclose wisely. Let the spectrum broaden as maturity increases. And if power-figures in your church are not mature enough to read beyond a narrow selection, then be discerning in your disclosure.
Alternatively, we could just read authors from our particular stream of Christianity, I know many who do this, but I suspect his would be a real mistake in ministry!
Biblical Preaching 
Peter, I wholeheartedly concur. My problem is that I seldom read from my stream (churches of Christ) either “liberal” or “conservative.” I do love to read lots of stuff from a wide variety of streams (I love Wright, Kaiser, Ryken, Peterson, Childs, Yancey, Carson, Longman, Long, Craddock, Willimon, Hauerwas). I find when I read an author a quote in the book takes me to another author and even more authors and new streams. I really feel my reading has enhanced my understanding of my stream without creating the need to leave the stream. I’m sure if some of my brethren knew the authors I read I might be labeled as well. It’s too bad that we do that to one another.
I agree about the importance of reading widely and the pastor must sometimes be careful to distinguish between those with whom he might disagree.
For example, I spoke to someone recently who si new to the faith and encouraged him to listen to a certain teacher on his iPod but I was also careful to tell him that this teacher differs from us in a few respects (mostly baptism) but overall, you will benefit from his ministry.
Also, I have been clear from the beginning of my time as pastor here to point out that I read widely because I want to benefit from the best everyone has to offer; such reading doesn’t necessarily imply wholesale endorsement. After several years of this, most people in my congegation now know this without my having to tell them.