I heard a rumor that Aptana is a great editor for JavaScript. I haven’t tried it, but Rick Strahl likes it, which is a good kudo in my book. Editing JavaScript in Visual Studio is “okay,” not great, so I welcome a better editor.
Aptana’s site also has a bunch of great video tutorials, for those of you who want webcasts.
Aptana Screenshots
“Code Assist” (Intellisense) for JavaScript, CSS, & HTML: