I was familiar with most of the plugins listed, but I learned about some new ones that caught my attention!
Headspace2: Headspace makes tagging and managing your meta data much more streamlined. Once activated, you can use Headspace to “suggest” tags for a particular post, which are generated from the content of that post or through Yahoo suggestions (you decide). You can also mass edit meta data, as well.
Robots META: Use Robots META to prevent the search engines from indexing extraneous or duplicate content areas like your search results, feeds, login and admin pages, privacy pages, archives and more. You can also use this plugin to easily validate your account with Google Webmaster Central and Yahoo Site Explorer.
This is definitely worth your review even if you feel familiar with WordPress and its capabilities.