What do you use, to create AJAX?

AJAX is the buzzword lately. And it will be for quite some time, I guess. But JavaScript used to be very underrated before AJAX became such a hype, and it shows in IDE support. A lot of text/html editors know the JavaScript syntax, but when it comes to codecomplete or even debugging, it seems the webdeveloper is left out in the cold.
Oracle’s JDeveloper only has syntax-coloring support for JavaScript. Netbeans has a (third-party) module that does basically the same. What other options are there? Is Visual Web Developer a viable option? And which ones are in the “affordable/free” range? Please comment.