As SEOs and webmasters we have a lot of work on our plate, and because of that we try to use any help we can get to speed things up and improve our work rate, make it as productive as possible. This is one of the reasons why we use so many tools in this line of work, well that and the fact that some things we simply cannot accomplish without using some tools, especially in the SEO industry.
My take is that you should use only what is necessary and which speeds up your workflow, in my case it seems that I use a bunch of tools, but I rely on each and every single one of them to scale my work and improve my productivity and results. These are the best SEO tools, no, the essential SEO tools for any webmaster or SEO if you want to have the best performance with your SEO campaigns.
1. Google Webmaster tools and Google Analytics