hey folks,
i wanted to know what are the most demanding skills a web designer should have. is the web designer and web developer same? coz i m a developer, mostly i work freelance and project based on designing in photoshop, html, css or jQuery (little), its been a little time since i been into it but i wanted to enchance my skills, many times i find myself working/fixing someone else code which has php and ajax and as i know little php, some folks really work bad and that got me thinking should learning php be a mandatory. ? not only php i wanna know which are most wanted skills a web designer/developer should have?
I wouldn’t say that PHP is a mandatory subject, if you work specifically in the client-side and your website is simple, you can do the job without it.
As for essential skills, there’s no one subject which is vital, there’s a multitude of languages like HTML, CSS and a knowledge of design that is essential.
most demanding skills (most difficult) =
IMO,
expert-level general security,
encryption,
‘expert-level’ regular expressions usage,
database security,
network security, etc.
most wanted skills
I currently know more about what is difficult, security is also a high-paying field*
*but many corporate jobs still require Microsoft knowledge, not Open-source.
You will find many opportunities in every area; I’ve been studying security & encryption lately. 
Have fun!