If you are building server images/templates and want to document how you've built them why not list the updates that are installed? Cool, but we can't copy-pasta the updates in bulk...These tools will handle this for you:
Windows Server 2003
If you are running Windows Server 2003 take a look at WUL (Windows Update List) a freeware app from Nirsoft. You can download it as a .zip which has the standalone version that doesn't require an install. Check it out @ http://www.nirsoft.net/utils/wul.html. Unfortunately this doesn't work for Windows Server 2008...
Windows Server 2008
So if your running Windows Server 2008 and want to export a list of updates, there is a built in tool to do this. Using WMIs Command-line interface (WMIC) you can export this list.
Launch a command prompt and type:
wmic qfe get /format:csv >C:\updates.csv
Also note that instead of a csv you can use these other format options:
CSV | HFORM | HTABLE | LIST | MOF | RAWXML
HFORM/HTABLE are HTML
LIST is Tab Delimited
RAWXML is XML