I think WYSIWYG editors are great, after your skilled with coding by yourself. If you don't know how the editor works, then your limited in what you can do.
I like to use notepad++ because of its features for XHTML/CSS, convert to XHTML is my favorite because it adds the doctype for you and does a very accurate job of converting all code to valid XHTML
And auto-submit to validatiors is useful. I used to just use notepad++ because it could have multiple files open at the same time but when I found out, it had macro support and a lot of other useful features, it is even more useful for me.