jQuery UI 1.7 Is Out With Tons Of New Features
jQuery UI 1.7 is out with a lot of new features, a better core architecture, and major theming improvements.
First of all, it is jQuery 1.3 compatible, so you will be getting the performance jQuery 1.3 has.
Also, every plugin is optimized to produce a better HTML output for a more flexible usage. And, there is a new progress bar plugin.
This new version comes with a new CSS framework that supports both jQuery UI plugins & any custom one to be developed Rather than the layout, the framework is concentrated on the UI design.