...
- Windows:
- Notepad++: http://notepad-plus-plus.org/
- UltraEdit: http://www.ultraedit.com/
- Crimson Editor: http://www.crimsoneditor.com/
- OS X:
- Textmate: http://macromates.com/
- Coda: http://www.panic.com/coda/
- Smultron: http://www.peterborgapps.com/smultron/
- Unix/Linux:
...