At work we update lots of computers using Windows Update. Windows XP and 7 all day long, rarely some Vista.
We do it through a corporate proxy, as connecting them to a domain to build a Wsus server is out of the question, so we download about two gigabytes a day of the very same updates everyday.
I've tried WSUS Offline. It's pretty complete but when it finishes it's common to be still missing hundreds of megabytes of updates, because its intention is not to fully update a system but to install the critical updates, as the developers explain in the forums.
Now I'm trying with Autoupdater. It's far worse, with poor capabilities for non-English Windows XP, but at least it gives the option to install non critical updates in Windows 7. It still misses hundres of megabytes of updates after fully updating the system.
And finally, both doesn't install the driver related updates of Windows 7, so they at most save us a couple of hundreds of megabytes and a reboot (with the associated login to the computer and to the proxy) out of three or four.
So, is it possible to somewhat extract the installed updates in a Windows 7 system and not having to download the same updates again and again at least with machines with the same hardware? Or even better, a generic package with all the updates?