jQuery 1.4 will be released January 14th (pun intended) , and will include a lot of new functionality. My favorites are synchronous animations, and lazy loader. Lazy loader allows you to load js or css on the fly.
Even though YUI does this too, it’s only a matter of time before YUI 3 becomes a 400 pound gorilla just like YUI 2.
They have posted a new site for the release, and to kick it off there will be 14 days of releases related to jQuery.