This seems like kicking in an open door, but how many computers running Windows do you know which aren't updated properly?

Windows Update itself has been updated, for the better, imho. One of the better new features (apart from the layout change) is the new Windows Automatic Updating, a feature that replaces the older Critical Update Notification. The name change reflects the new features: instead of just getting a message whenever a new update is available, you can install the update immediately! A small set of options is available, giving you control over when or if you will be notified, and when downloading starts.

As far as I've checked, these new updates are applicable for Windows 2000. If I'm correct, new XP machines already had these features available to them. I'm not sure what happens when you try to update any older version of windows (NT, ME, 9x). I don't have any computers available here that run those OS's. Could anyone give those a try, and report back what happened?

Update your system now. Visit http://windowsupdate.com.