1. The Periodic Table of SEO Elements
This infographic by Search Engine Land provides a great reference for the key SEO factors and a ranking of their relative importance.
2. How Much Does SEO Cost
This provides great insight into what SEO costs based on survey data across the industry. The most common hourly rate charged in the US is $101-$150/hr according to the survey.
3. The Google Panda Update One Year Later
This infographic does a great job of illustrating the essential concepts of the Panda Update and how it can affect your site.
4. Goldilocks SEO
SEOBook provides tips on how to implement SEO in an effective manner that is not overly aggressive or too passive.
5. Link Building Anatomy 2012
A nice summary of good link building techniques in 2012 including creating valuable content like webinars, slide presentations, and video tutorials.