I have many updates to report on since I last wrote. Firefox, Flash, Windows, Office, Mac OS, QuickTime, and probably more that I am forgetting. All of these updates are important, and most will prompt you to update; you just have to make sure you do it and don't put them off.
The February Windows updates released this week are quite important; they fix a number of important vulnerabilities. As long as you have Automatic Updates turned on, you should get all of the important security related ones, including the patches for Office. For Office 2004 for Mac users, there is an update for you too!
As long as you are running any version of Firefox 2.0, you should get prompted for the Firefox 2.0.0.12 update that was recently released. If you are not sure what version of Firefox you have, this past posting can help you figure it out.
Apple's Mac OS X v10.5.2 / Security Update 2008-001 patches a few, but important vulnerabilities. For more info in this and the QuickTime patches, see Apple Security Updates.