As far as WYSIWYG JavaScript HTML editors, you might take a look at TinyMCE as well. It's used by many CMS packages as an option or as the default visual page editor. That includes Mambo, Joomla, Drupal, and the venerable Citadel.

I've recently updated the TinyMCE plugin for Lucid to use TinyMCE 3.0.6, and I should be getting that posted to the repository Real Soon Now (once I have some more testing and feedback).

Besides being fairly easy to make into a plugin for a CMS, it's pretty easy for a JavaScript programmer to write plugins for TinyMCE itself. I should know, because I'm not a great JavaScript guy and I've done a few. The plugin model was one of the changes between the 2.x branch and the 3.0 branch, so I've actually written and rewritten a few.

The license for TinyMCE is LGPL, so if you're looking seriously at licenses that's good to know.

ALl that said, HTMLArea I hear is pretty good, so don't let me dissuade you from it if it ends up being a better match for your needs.