Platinum SEO Plugin is the ultimate wordpress SEO solution.Platinum SEO Plugin offers all the features of All in One SEO plugin plus more. Platinum provide an ultimate onsite SEO (search engine optimization) solution for wordpress blogs. If you are already using All In One SEO Pack, this plugin will automatically import all the settings, that you have defined using All in one SEO plugin. You can check out the features of Platinum SEO Plugin:

• Optimized Post and Page Titles for search engines
• Generates all SEO relevant META tags automatically
• Helps you avoid duplicate content
• Lets you override any title and set any META description and META keywords, for any post or page
• Compatible with most other plugins, like Auto Meta, Ultimate Tag Warrior and others.However you may have to disable All in One SEO pack
• You don’t have to fear changing permalinks. If you are not satisfied with the current permalink, change it through Settings–>Permalinks in your admin panel, without worrying about loss of Page rank or google penalty.Platinum SEO plugin will take care of issuing a 301 redirect to the new location.This is a new essential feature, not present in All in one SEO
• Add index, noindex, follow or nofollow, noarchive, nosnippet, noodp, noydir meta tags to any post/page.These options are not available in All in one SEO Pack.

Pricing: Free
Requirements: WordPress 1.5+
Source: http://wordpress.org/extend/plugins/platinum-seo-pack/