Performancing is a neat tool that gives you WYSIWYG HTML editing and a decent entry preview, along with tools for adding Technorati tags to your pages (and adds a Blog This context menu item to Firefox). You can even save content locally for future use as Notes. Just click the status bar icon to open the blog editor, and start typing.
I've been using it for a little while already - and have grown rather fond of it.
Technorati Tags: performancing, blogtools, firefox