PSPad is one of the most productive text editor I've ever seen.It is possible to open a hughe number of file types.
I'm excited about user-defined highlighters. This is one of the best ideas that could be part of an editor. I'm working on IEC61131 code and it was a good way to coloring the code instead of stupid black code lines.
My most used feature is the text difference viewer fucntion. It helps me to get a quick overview of recent changes in my code.
Last but not least - this app is for free :))))