The most important question is should we learn programming languages to become an Ethical Hacker? The answer is both yes and no.You can be a good ethical hacker without knowing any programming.You can do effective hacking with a better understanding of security tools.The problem is that even if you know the background working of a tool ,most people will classify you only as a script kiddie.
Understanding Programming languages will open a new world of hacking for you.It will also help you to write exploits and Hacking tools .Better knowledge in programming languages will definitely lead you to become an elite hacker.
I believe we should start with Web Hacking .So learn HTML First .
Nowadays majority of websites are written using PHP and Mysql .So it is a must to learn PHP to understand the mechanism behind Web applications.
When we come to exploit writing C and C++ is a must learn programming language.C and C++ makes up more than 50 % of Exploits available now.
Python and Perl
Both of them are considered as scripting languages.Python is simpler to write and understand than Perl.Alsolearn Python Socket Programming ,which will help a lot in exploit writing.
Perl is also used widely for exploit creation but it is much difficult to understand when compared to other languages.So i recommend Perl after Python.
You can use these websites to get started.
C and C++