I use GNU Emacs a lot and feel so comfortable with this Editor that I prefer using it for my TYPO3 development instead of switching to one of the so called modern IDEs. To improve the editing features with respect to TYPO3 I developed a TypoScriptMode and a TypoThreePhpMode. Both of them where born from necessity and might be improved from time to time.
Welcome to the wiki – even if the welcome is about five months late! – AlexSchroeder