Learning a programming language might take time, so you need to be patient. Focus on learning to think like a programmer instead of learning individual languages. Focus on similar concepts in all programming languages.
C and C++ are the languages that Linux and Windows were built with. It (along with assembly language) teaches something very important in hacking: how memory works.
Python and Ruby are high-level, powerful scripting languages that can be used to automate various tasks.
PHP is worth learning because the majority of web applications use PHP. Perl is a reasonable choice in this field as well.
Bash scripting is a must. That is how to easily manipulate Unix/Linux systems. You can use Bash to write scripts, which will do most of the job for you.
Assembly language is a must-know. It is the basic language that your processor understands, and there are multiple variations of it. You can't truly exploit a program if you don't know assembly.
