No 2. SEO Smart Link

This plugin provides you with the option of automatically linking keywords, phrases and comments of your posts to the corresponding posts, pages, categories and tags. It also allows you to set up your own keywords and matching URLs. It is one of the most complete SEO packages available for WordPress.

Go here to download.

No 1. All-in-One SEO Pack

This plugin will automatically optimize your blog for the search engine to the fullest. It allows you to customize the post title, post description and post tags for all the posts individually. Furthermore, this plugin also features advanced canonical URLs and built-in API.

Go here to download.