I've actually gone backwards recently, in terms of technology.
I now write exclusively with pen and paper. I do this for three reasons:
1) There is no internet, files, or computer games to distract me.
2) There is no backspace key, so I don't have the luxury of quick and constant editing. This forces me to focus more on forward progress rather than backwards altering.
3) It's portable and requires no electricity or battery charge.
Then I just type up what I've handwritten into a file, but at that point, any word processor will do fine.
Oh and, between the two (StoryBook and YWriter5), I prefer YWriter5.