It's been bugging me ever since I got this machine with Vista preinstalled that I couldn't hide updates I don't want. It was easily done in XP.

Finally, I found a way. Maybe everyone else in the world except me knew this, but I thought I'd share the info in case there's someone who doesn't know it:

Simply right click on the name of the update and select "Hide update" from the little drop-down menu. Also, there's a small bonus there that allows you to get a little info about the update by selecting "View details."

Happy hiding!