Seems like everyone has a favorite editor. And yet more editors happen. I wonder what percentage of programmers haven't built an editor at some point?
http://www.c2.com/cgi/wiki?GreatVimFeatures
http://www.c2.com/cgi/wiki?GreatEmacsFeatures
http://www.c2.com/cgi/wiki?GeneraOs
http://www.c2.com/cgi/wiki?RefactoringBrowser