The update located in Software update is a delta update (only updates what is needed) and this one can cause issues including freezing and screen distortion.
DON’T DOWNLOAD THE UPDATE FROM SOFTWARE UPDATE.
Update 5 Feb 2012: The delta update has been removed from Apple Update service.
There is another type of install – a combo update – and this updates everything and it has been reported that this update is error free.
If you receive regular health checks from us then you don’t have to do anything – it will be done during your next check.
If you need to install it yourself I recommend you get it from the Apple downloads page and be sure to download the Combo installer.