Since this editor is going to be used (at least in our case) by the editors of the site and since we are using Mozilla as the standard browser, we are looking into Mozilla Editor, as pointed by Jun. It's really neat and works very well. The problem is that if you were to provide a functionality for people to edit their pages in a community, well, 95% of -at least our- users are using IE... :( ... but maybe we could just tell them: "you use IE? No WYSIWYG for you" ;).
Just my 2 cents
