I gave a talk on E4X. In a Just and Decent world, I wouldn't have to write a blog entry on this, because there would be a nice front page to jerakeen.org that listed all the recent things I've done, with the option to subscribe to RSS (or whatever) feeds of various subsets. But I've been too lazy to write this so far, so I'll just link to it here until I get django to do what I want.
E4X is a lovely extension to JS (well, compared to messing with the DOM, and it's in core, so embedded users get it too), despite its crazy inconsistent syntax and annoying brokeness in Firefox. Fortunately, I don't have to care about web browser-based JS implementations, so I get to use it, and you don't..