jQuery is in Drupal core!
After a long wait, the awesome jQuery library has finally been committed to Drupal core. jQuery 1.0 will be part of the next major Drupal release, for which the code freeze is about to begin.
While we did take advantage of jQuery to add some minor glitter to our JavaScript features, the main advantage is that it makes it easier to develop JavaScript features. Using a simple CSS-based syntax, you can manipulate any element in the page easily. Loading in chunks of HTML through Ajax is a snap too.
Hopefully jQuery will help more Drupal developers look at using JavaScript to build kick-ass interfaces in the browser.
Thanks to John Resig and the jQuery community for making such an awesome library. On the Drupal site, thanks to: Konstantin, Steve, Angie, Ted, Jeff and everyone else who tested the patch.
See also: 'New Wave' JavaScript in Drupal: jQuery.
PS: There will still be some bugs in there that I haven't found, but that's what the code freeze is for ;).