I think it’s important to read not just within your chosen genre, but also outside of your normal comfort zone as well. The more I read, the more ideas are generated and this can only help my writing. Reading only within a narrow area can, in my opinion, be dangerous, because the ideas will have already been used within that genre of writing and it can be easy to copy someone else’s ideas without intending to.
On the other hand, my ideas can come from anywhere and anything. I might generate an idea for a plot or character from a novel, a nonfiction book or even a play. I like to read older books such as classics, as well as the ones that never quite made it. These are great because when the ideas begin to appear they can be changed in so many different ways when being filtered through a modern world.
To me a writer’s mind has to be fed before it can generate ideas and the more we read, the more ideas we’ll be able to generate. Another thing is that the more we read the more we find ourselves taken away from our own work and this distance gives the work space in which to grow. I read short stories, novels, plays, textbooks, biographies, poems and even song lyrics.