Software for Creative Thinking

I have been working on the Law School 2.0 book in some software designed for large writing projects called Scrivener, and I have found it to be terrifically helpful.  Using Word for large scale projects is hard because it acts like a fairly dumb "bucket" of words.  But Scrivener, and similar writing software, supports the creative process in numerous ways.  It has a "corkboard" where you can move "index cards" of ideas or chapters (or both) around and see how they line up.  You can save your research within the program, and thus switch from the research and back to the writing easily.  And you can make the program disappear, and leave you with only the writing "surface" on the screen.  At some point, I will have to export the work into Word - so it can be accessed by editors.  After that, it will have to stay in Word.  Fortunately, Scrivener has a highly customizable output feature to Word, so it is easy when you are ready to leave the program to transition back.