Use JQuery. It’s Officially Supported Now!

http://weblogs.asp.net/scottgu/archive/2008/09/28/jquery-and-microsoft.aspx

The jQuery intellisense annotation support will be available as a free web-download in a few weeks (and will work great with VS 2008 SP1 and the free Visual Web Developer 2008 Express SP1).  The new ASP.NET MVC download will also distribute it, and add the jQuery library by default to all new projects.

We will also extend Microsoft product support to jQuery beginning later this year, which will enable developers and enterprises to call and open jQuery support cases 24x7 with Microsoft PSS.

Going forward we'll use jQuery as one of the libraries used to implement higher-level controls in the ASP.NET AJAX Control Toolkit, as well as to implement new Ajax server-side helper methods for ASP.NET MVC.  New features we add to ASP.NET AJAX (like the new client template support) will be designed to integrate nicely with jQuery as well. 

We also plan to contribute tests, bug fixes, and patches back to the jQuery open source project.  These will all go through the standard jQuery patch review process.

Impressed am I.