I needed to upgrade someones computer to Windows 7 and they had a very slow internet connection. To save time, I wanted to download all of the updates ahead of time so I wouldn’t have to wait an eternity for them when I was on-site. I initially considered setting up a WSUS server inside a VM but stumbled across another solution in the process: WSUS Offline Update.
I simply downloaded and extracted the zip file to an external hard drive, ran UpdateGenerator.exe, selected the products I wanted and then let it eat overnight to download all the packages. I then took the external hard drive with me, attached it to the machine after I installed the OS, ran the UpdaterInstaller.exe (located in the client directory) and in very short order had (almost) all the Microsoft Windows, .NET, VC++ Redistributable, and Office updates installed. On a Windows 7 Professional x86 machine, Windows Update still found about 18 packages totaling 38MB that needed to be downloaded after WSUS Offline Update had done its thing. Not perfect but sure beats downloading a gig+ over a slow connection.
I’ve also used the app to update new VMs when I create them, as it’s still faster getting them off the disk than the internet, even with a fast connection.