The Rich Text Widget was working for me, up until I changed the directory of my wordpress install to be different from my blog address. The problem is that the config file assumes that both of these will be the same. The first two lines of the config.php for the plugin looks like this:
define('RB_RICHWIDGET_BASEURL', RB_RICHWIDGET_SITEURL . '/wp-content/plugins/rich-widget');
I changed the first two lines (and added a third in between)...
define('RB_RICHWIDGET_BASEURL', RB_WPURL . '/wp-content/plugins/rich-widget');
Also - I wanted more buttons on the rich text editor than what was provided... I changed this by finding fckconfig.js in the fckeditor folder. At about line 122 - you'll see:
FCKConfig.ToolbarSets["RBRichWidget"] = [
I changed that second line to all this:
Just putting that out there in case that helps anyone else...