I consider myself someone who has a pretty broad knowledge base. By virtue of changing my undergraduate major 8 times and changing my dissertation topic and then going into a technology field related to education, I know a fair amount about a lot of different things. But I also know a lot in a few areas. One of the reasons I was leery of pursuing a purely academic career was the seeming requirement to focus on one narrow area of study. Certainly I know faculty who function this way. They know their area, usually a fairly narrow one, and very little else. Oh, sure, they can contextualize their area, say 19th century diaries, in a broader context of all diaries and of all literature. They know influences and antecedents. In smaller schools, faculty are more likely to have to venture out of their area in order to teach classes in related areas.
But I'm still often surprised by people who don't venture much beyond their disciplines. They don't care how history relates to science or vice versa. And forget popular culture. They don't watch tv or listen to the radio. They don't know that their students were obsessed with "The O.C." and were sad to see it go. "Lost" is what they are when they venture into the wrong neighborhood. They know more about things that happened 50 years ago than what's going on now. This isn't all faculty, of course. I've run into many who share with me a general curiosity that extends to many areas, including popular culture. And I'm no cultural maven myself. I never really liked Lost and my tastes in tv lean toward reality shows, The Daily Show, and The Simpsons, not exactly the intellectual or coolest of fare. I don't have a craving for mysteries the way many of my faculty friends do nor do I stick to reading "the classics." I like nonfiction related to my field and in areas I used to study but no longer research--economics, history, cognitive science.
I can appreciate faculty who lament that students have no sense of history or context, no understanding of the complex world around them. But I also think that faculty should appreciate that some students understand their complex world in different ways than they do. Social networking, for example, complicates relationships and identity for students in ways that most of us never had to contend with as young people. TV shows and movies are often more complex commentaries on culture than the shows and movies we watched at their age was. A broad knowledge can provide students with even more ways to contextualize their experiences, but we shouldn't dismiss certain ways of looking at the world just because it's not our discipline. Disciplines can inform each other, always have, though we're not always aware of it.
I can't imagine not having a broad knowledge, not understanding science at all because it's so different from English as a discipline or dismissing popular culture because it's not "intellectual" enough. That seems, oddly, a shallow way of approaching the world.