jQuery 1.3 Beta
If you want to help test, all the details are here. Many rewrites of core areas like the selector engine and DOM Manipulation (append/prepend/before/after).
Dan Rubin hits the nail on the head with a great way to handle columns of equal height.
WordPress "Art Direction" Plugin
Not all posts are the same, so why are they all designed the same? This plugin will allow you to apply styling that is unique to that post in WordPress.