It's update Tuesday for Microsoft. There are 7 update bulletins that cover fixes to more than 11 different vulnerabilities. In addition there is a critical manual update for Internet Explorer on Windows XP clients that needs to be applied.
If you are still running Windows XP (which Microsoft is dropping security support for in February) you need to install this fix-it patch. You should install the patch even if you are not using Internet Explorer as your default browser. If you are using IE 9 or 10 you don't need the patch.
If you are using Windows Vista or Windows 7 you need to make sure you are upgraded to IE 9.
UPDATE: Adobe also release security updates for Flash and Adobe Reader today.
