nuinu

This plugin uses custom fields to allow the page title tag to be different from the actual page title.
Both meta descriptions and keywords can also be added to pages.

SEO nuinu

Customize pages and posts meta title, descriptions and keywords directly in post or page edit window in wordpress.

Chad Hovell

Select extra layouts from the post editor Screen Options menu. 
There are now 24 variations to choose from!

Three Column Screen Layout

Three, four and five column screen layouts for the post editor.

SEO nuinu vs Three Column Screen Layout