Which is the best SEO tool for searching?

All SEO tools can profit your site optimization. There is no "best tool". the most important thing you can do, in my opinion, is to start with a keyWord research in order to form a complete SEO strategy .

• For desktop search engine for google, Yahoo, MSN

http://www.greymatterindia.com/it-services/total-toolbar-deskband.asp

• Firefox and internet explore toolbar for search engine google, Yahoo, MSN

http://www.greymatterindia.com/it-services/total-toolbar-deskband.asp

Im always using google toolbar and seobook.com tools.

have a look at http://www.freesearchengineoptimizationtools.com