By latest statistics - PHP is preferred by of the world's web server software for its flexibility, database support, interactivity and abundance of Frameworks.
We don't mention software developers on this site often enough but it would be a crime to not have a cheatsheet for this group after catering cheatsheet
A must read infographic on the key differences between HTML vs CSS that covers html vs css basics, backgrounds, uses, website applications, etc
Learn to Code at Home - Infographics Gallery Showcasing the Best of the Best.
11 Essential Tech Skills You Need to Get Hired as a Web Developer (Lifehacker)
"Life of a Front-End Developer," infographic design by Skilledup.