I have found that most writing software is either condescending to the writer (if you don't already know about the basic elements and structure of fiction, you should take a class rather than buy software that talks to you like you're a moron), or so cumbersome to use that you lose your creative drive and spirit in the effort to keep your jottings organized. Still, I'm always hopeful that someone will come up with a program that can manage hundreds of scattered notes and vignettes, and can keep me from going off on wild tangents that have nothing to do with my story, all without making me feel like I'm cheating the artistic process by reducing it to an idiotic formula that would be an embarassment if anyone found out about it.
I'm trying out newnovelist software, developed in the UK and edited by the great great-granddaughter of Charles Dickens. The program takes you through six stages of writing your novel by forcing you to think and write about each element of character and plot development. I'll report back in a couple of weeks on whether I think it's a useful tool for combating writer's block or just another method of procrastination.