Users who want to update their Windows operating system can use the automatic updates feature to download updates for Windows automatically, visit the Windows Update website in Internet Explorer or use one of the several Windows Updates downloaders like Autopatcher or Windows Updates Downloader.
A third possibility came to light recently with the introduction of the Windows Update Catalog. Like the Windows Updates website the Windows Update Catalog only loads properly in Internet Explorer. It does offer however a nice and convenient way of download all updates for Windows in one go from the official Microsoft server.
The website features a search form that searches the entire Windows database of patches, updates and applications. Entering a generic name like Windows XP returns more than 1000 results which means that it makes sense to reduce the results by narrowing down the search.

Instead of searching for Windows XP a user could search for Windows XP Security Updates or Windows XP KB. Items can be added to the basket from where they can be downloaded at once. The updates will be stored in a selected folder from where they can be installed.
The Windows Update Catalog offers an enhancement by introducing the basket which makes it possible to add all files to it before downloading them in one go. This is a great way of downloading all updates for Windows in short time.
It is missing a few features like filtering search results by operating system or language which would greatly reduce the hits and time spent on the site.
Related posts:
Windows Updates DownloaderMicrosoft August 2008 Security Updates
Download Windows Vista Service Pack 1 Beta
Microsoft February Security Updates
Microsoft releases security updates for XP and Vista


is it possible to download updates/patches/service packs only once and have them available for installation everytime we need to reinstall windows?
if yes, is there a way for the already installed updates to be reinstalled after formatting the OS drive and installing vista from the old recovery disk?
http://www.vulnerabilityassessment.co.uk/ctupdate.htm
This thing is like A God in the IT industry as it allows for offline update installs and it’s automated.