New BETA release of Secunia PSI
"Now available from Secunia is the BETA release of the latest PSI.
Amongst the usual programs PSI scans through for needed patches, the
new version will now also tout a feature called 'Secure Browsing'.
The new feature informs users of what programs and plugins are
integrated directly with their browsers and any security issues
affecting the browsers and their plugins."

I think that Secunia's PSI fills a unique niche.  Being able to see which of your packages is out of date is a valuable tool that Microsoft does not provide for non-Windows binaries.  Keeping up with patches for your system binaries is important.  The newest Beta version appears to be looking at your plugins for your web browser, too!