I noticed that you requested a description of the SEO plugins...I am not familiar with everything on the list however I do use All in One SEO.
All in One SEO essentially optimizes the pages on your website for you automatically and makes them search engine friendly. When you install this plugin on your site, it gives you the ability to specify the keywords that your site focuses on as well as create a description of what it is that your site is about which also can help with SEO rankings.
Another important feature is that it lets you give titles for your website that display in the browser's window bar. If you're not sure what I'm talking about, if you look in the upper left hand corner of your browser you will see that it has a title. On this particular page the title is "Choose Top Ten Plug-in For Better SEO - Small Business Ideas Forum" When the pages of your site have titles like this, it makes them descriptive and much easier for the search engines to find them and All in One SEO gives you the ability to do this on your sites.