1.) Security Updates to correct vulnerabilities and exposures.
2.) Hot Fixes to correct usability and/or functional shortcomings.
3.) Performance updates to add new features, improve speed, update the version iteration, etc.
Of the three, security updates are almost always the most important to apply as soon as they're available. Internet linked computers are susceptible to innumerable threats. The general consensus is that this is especially true of Win32 machines (the cause: a combination of historically dodgy, security tone-deaf design and the target rich environment of a near desktop monoculture MSFT created).
Fixes are next in line in my view. Sometimes (usually) these are harmless but as you've recently experienced it's all too common for new conflicts and headaches to be introduced.
Finally come the performance or 'user experience' updates. With the possible exception of version updates these can be accepted or rejected on a case by case basis without too much worry. For me, the question to ask and answer is: does this update solve any problem I'm concerned with?
Hopefully, this brief overview was helpful. I think however, that your real question is how to minimize the risk of future heartache from these updates.
I suggest the following:
a.) Set Windows Update to download only security updates and notify you when these downloads have completed (giving you the ability to determine when they're applied). See the links below for how-tos.
b.) Investigate how to configure the updating features of the apps you use -- such as Adobe. Where possible, turn off automatic updating, choosing instead notification of an update's availability. This will give you the chance to do some Google research on known issues before proceeding with software modification.
Here are links to articles explaining how to configure Windows Update:
Using Windows Update (a generalist guide)
<http://helpdesk.wisc.edu/page.php?id=2121>
Understanding Windows Update (a more comprehensive overview from MSFT)
original link -
<http://windows.microsoft.com/en-US/windows-vista/Understanding-Windows-automatic-updating>
shortened link -
.d.