Auto Patching Windows
I actually saw this mentioned in my last Maximum PC magazine, and wanted to mention it here, mostly for bookmark purposes.
Autopatcher is an all-in-one updater for Windows 2000, XP, and 2003. If you're sick of going to Windows Update all the time, this includes every patch and update from Windows Update as well as a pile of registry tweaks, add on software, and other cool stuff. I just plan on burning this to a CD to bring to when I do a service call, and call it good.
The same group also has an Autostreamer, which gives you a slick interface to slipstream and create a new Windows installation CDs that are updated with the latest service pack. Dang cool.