Not only is it so much faster for browsers to load, the content is easily spidered by the search engines and it’s flexibility knows only the bounds of your imagination. I code purely in CSS and write all of my code by hand. No CSS editors or DW selectors. Keeping the code clean and manageable as well as cross browser compliant are always challenges when writing CSS and over the past few years I’ve become quite skilled at it. I love those style sheets.
PHP has become an extremely powerful tool in day to day web design. I commonly use my library of scripts and snippets on most sites I design and build. Everything from hooking up to a CMS system to running complex online forms and user feedback items.