Mozilla offers an expanded version of the Adobe Flash Player check that you might see after a Mozilla Firefox update but this site covers a number of other plugins and works for more browsers than just Firefox. The Plugin Check site checks at least Adobe Flash, Java, QuickTime, Silverlight, Adobe Acrobat, and many other plugins. It will report the version if it’s running the latest or state if the plugin is vulnerable. For many of the popular plugins, it also provides a link to go straight to the source and download the latest version.
If you’re used to searching for the Adobe Flash version check or ‘What version of Java do I have?” pages, check out http://www.mozilla.com/en-US/plugincheck/ for an easier way to find out your plugins version info and stay up to date. Now if you’ll excuse me, it looks like I need to go update Adobe Flash, Acrobat, and QuickTime.