It's a good news for all JQuery lovers. The latest version of JQuery 1.4.1 has been released and getting very popular. Personally, I feel very good. The secret of success this version is the performance improvement, some changes to existing methods and new additions. This is very nice to know the functions are executing less time than they were.
They have made plenty of changes to setter, getter and ajax methods.
The whole API changes are documented here.
Why to wait, get the latest version and start playing with it.