An updated version of the PluginWatcher extension (version 1.1) is now available for download from the Mozilla add-ons website. It is currently in the sandbox, awaiting approval from an editor.
The new version primarily adds the ability to customize PluginWatcher's UI while also introducing a number of changes to the core of the extension. In the UI department it now also offers a second panel, displaying the plugin activity expressed as a percentage of utilization. The biggest change, however, is in the way the extension calculates the plugin load on the system - that algorithm has now been refined and it should prove to be significantly more accurate. This release also addresses some of the packaging issues that were observed with the previous xpi; mainly it provides a much cleaner and smaller xpi file, containing only the files that are required by the extension.
I also plan on releasing version 1.2 of the extension soon, as I already have a number of ideas for possible improvements. If you care to try the new version, it can be downloaded here (since it is still in the sandbox, you will need a Mozilla add-ons account to install it). Feedback is as always welcome.