http://www.autopatcher.com/Windows only: AutoPatcher is a freeware Windows Update alternative that gives you more control over how you update your PC.
Rather than requiring an internet connection every time you need to update a PC, AutoPatcher can be burned to a CD and used on any computer - which comes as a godsend for any resident PC-geek of the family, especially when you've updated a PC over a 56k modem. The great part about AutoPatcher is that not only does it dole out the regular updates, but it also automates installation of several tools not generally included by Windows Update, like Windows PowerToys.
The only downside to AutoPatcher is that you can't automate future updates, meaning that you would have to check back monthly to get the "Update" releases. If you're fine with that, then go with AutoPatcher all the way. If you don't want to worry about checking back with AutoPatcher for updates, the regular Windows Update tool should remain turned on and updating. However, you should still keep AutoPatcher in mind any time you've re-installed Windows, as it provides a much easier and arguably secure way to update a freshly installed, unpatched version of Windows.