One of the few things that annoys me about Windows is that it's fairly difficult to get a real Markdown (http://www.daringfireball.net/projects/markdown/) parsing system set up. I really LOVE just writing in plain text/Markdown, then converting, and wish it were easier to do for me for non-web writing.

Something generalized from Markdown would be phenomenal as a stand-alone editor, i think -- have a "code view" and a "display view" as if it were HTML, but marked up as rich text instead.