Having tested a handful of WYSIWYG plugins for WordPress, the best one I’ve come across so far is FCKeditor. FCKeditor replaces WordPress’ current editor with one that has a lot of additional features. To make it even better, it even writes pretty clean code.

Additional features, besides those found in WordPress, include:
- Font face, sizes and colors.
- Its own built in image uploader along side of WordPress’.
- Flash capabilities.
- Post Templates.
- Paste from Word & Paste plain text buttons.
- Find and Replace
- Forms
- Subscript and Superscript text.
- Link Anchors
- Custom Smilies
- Special Characters
- Page Break
- Custom Styles
- Tables
- & More
Another great feature is the full screen editor. Hit the button and your whole browser window turns into the editor for maximum screen writing space.