To be noticed that WordPress 2.5.1 release. It includes security fix. So I recommend you to upgrade as soon as possible.
* Performance improvements for the Dashboard, Write Post, and Edit Comments pages.
* Better performance for those who have many categories
* Media Uploader fixes
* An upgrade to TinyMCE 3.0.7
* Widget Administration fixes
* Various usability improvements
* Layout fixes for IE
2.5.1 has over 70 fixes. Don’t waste your time and put your Blog under security shadow. Download it now and upgrade it.
It is really need to update.