Sssh, Reading in Progress

Some fiction writers say they can't (or don't) read fiction while working on a project. I find it depends on the stage of writing that I'm in. Sometimes in the midst of something, I find I really really need to read something brilliant and inspiring (in which case I turn to something I've read before and know to be good), sometimes it doesn't matter and I can read anything, and sometimes I can only read nonfiction. These stages seem to correspond with whether or not I'm trying to find the voice of the piece (requires inspiring reading), whether I'm happily in the midst of the piece (read anything), or whether I'm trying to solve some problem, either in drafting or revising (read nonfiction). Right now I'm moving between two nonfiction books, Collapse: How Societies Choose to Fail or Succeed by Jared Diamond and The 9/11 Commission Report (which is well written enough to surely have had some English majors on staff). These reading choices have to do with the fact that I am trying to solve a problem while revising my novel, but also because I've started thinking about my second novel and they're prompting new ideas.