This workflow thread might also be of use - the chart listing all the various tools is updated as of 11 days ago.
For my contest entry game, I used Notepad++ but then switched to CSIDE, as I found it easier to control testing and formatting together with the writing.
For a short story and contribution to Zombie Exodus: Safe Haven I used CSIDE exclusively.
Now I am learning Scrivener and plan on using this for my next project starting with the outline all the way to the manuscript and then move the project to CSIDE for scripting and testing.
Scrivener is a joy to use - I have everything that is normally all over the place in one container and I am able to use and manipulate all the notes, graphics, text files and character/locale sketches in multiple ways, including linking key words across multiple documents and the tracking of all sorts of project goals.
Scrivener will also allow me to switch the format of the project from a CS game to a novel, screen-play or any other writing I may want to use my subject material for in the future.