Uhm, if I hadn't to use a WYSIWYG I think Notepad++ would be good as much.
..but the questions are:
1. It is really necessary a plain text editor?
2. In that case, how to convert/create/compile/build (which one? XD) an appropriate file?
3. Which language I have to use?
4. Which file type?
If I have to to use plain text file as raws I hope they have to be (X)HTML and CSS (less probable..) because they are the better known mark-ups.
Thank you a lot!