I haven't tried them all, but my text editor of choice is definitely NoteTab Pro
I've been using it for 5-6 years and functionally very rich. Some of the advanced features can take a bit to learn, but very worthwhile.
Most friends use the Lite (and free) version and there's only a few advanced features not available.
Too many features to list, but one very productive one is writing your own paste clips, macros, libraries etc, very powerful.