One of the largest updates in the past year is being prepared for release on Update Tuesday, 09 June 2009. This batch of update is made up of 6 Windows updates and 4 updates for other Microsoft programs (IE, Word, Excel and Microsoft Office).
Six of them are considered critical; three important and one is moderate. All of the critical issues are due to the possibility of remote code execution; the important ones relate to the elevation of privileges and the one moderate issue is related to the information disclosure.
You can read more info about these bulletins and sign up for your own copy of the advance notices at the Microsoft Security Bulletin Advance Notification page.
These bulletins are a terrific way to stay up to date on security updates to your Microsoft software.