As far as story structure software goes, Power Structure and Save The Cat! are the two I've tried so far, and of those two I'm still fairly new to STC.
There is, though -- now that I've looked over the Software section one more time -- a Screenplay composition software you've missed, as well, and a fairly good one: CeltX. (
http://www.celtx.com/). Having tried CeltX also, I'd say it's comparable to Movie Magic Screenwriter -- if perhaps not Final Draft -- and it's got one very large selling point: it's completely open-source and *drumroll, please* FREE. Can't beat that with a stick.
