todoPad
Overview
In One Sentence
todoPad is a simple text editor with syntax highlighting for todo.txt files.
In More Words
Think Notepad with some colours/bold font, and you're there.
todoPad highlights task priority, creation date, and any projects or contexts you have. Completed tasks are shaded gray and italicized.
todoPad is written in C#, and targets .NET 4.5 (though it might work on earlier versions of the framework.)
Rationale
The todo.txt format is beautifully simple, easy to use, and effective. Unfortunately, most todo.txt clients tend to mimic more traditional task management apps; there's a set process to add or edit tasks, with dialogs and items to click.
That makes sense on a mobile device, but on the desktop it doesn't really work too well: why bother, when all you really need is just the raw text? Notepad fit this bill very well.
But everything looked a little plain. And so here we are.