I have learned html and css, which I believe myself to be decent at, but I want to know which language to learn next. I feel as though I am done with learning any kind of web design language, and wish to move on to web development. The question stands; which language should I begin to learn next?
For very sure you should consider
Server Side(optional) : ASP.net or PHP or Perl
if you plan to be a back end developer, to learn Perl web programming first to get a complete concept, then select ASP.net or PHP to study indepth. As well, you need to select a DB server to use as well, MS-SQL or mySQL is ok. You can select LAMP/WAMP platform.
If you plan to get a web job, you can consider to use IIS+ASP.NET or Java stuff.
P.S. I am currently a programming newbie and I have decided to start with Python. Then I will learn C++/Java and PHP. You can also take the same route.
PHP is a MUST for a web developer.