Grant McCracken has an interesting post at his blog about his conversation with a fluid writer who happens to work for a major corporation. What this conversation reveals to McCracken, is that business writing needs to learn a thing or two from literature, even citing a new business book that uses poetry within its pages.
He states, "What we want is a "management literature" that reads like literature. Why must our writers work for the corporation and write, like Wallace Stevens, as if in another life? Everything in the corporate world is now changing...why not this?" I agree. It could make some books more interesting beyond the first 15 pages, but more importantly, it would help us understand, process, and reflect on the material differently, which can't hurt. As business thought drives toward shorter content, this would also be a way to make a stronger case for writing a book in the first place, and potentially ensure your name on the shelves among the classics.
Even if that's not the case, literature is an important consideration. No matter what you're writing, reading books (all kinds) will help. If those non-business books start to have an effect on your content and delivery, it will set your style apart from your peers.