The only downside to this IDE is that it is a beast to load after restarting one's system. It takes well over five minutes to load on my Macbook Pro i5.
What about Markdown?
It's one thing to write out a markdown file, but what if you want to see what your document looks like before publishing? Mou is a free markdown editor for Mac OS and better features than the MarkdownPro in Apple's AppStore. MarkdownPad is a full-featured Markdown editor for Windows.
Pick apart a corporate logo into a color scheme in seconds with ColorSchemer on a Mac or PC. The program is tight and simple to use.