The best language to learn is............

As many as you can.

If you want a language to start learning with, I suggest C/C++ because many of the other languages were written with a similar syntax to these. If you learn C/C++ first, you can pick up other languages a little more easily (in most cases.) If you want a good scripting language to start with instead (if you don't want to mess with a compiler) try Perl, or TCL. Both are excellent. TCL is a little easier to learn IMHO, but Perl will stand out better on a resume.

Good luck.

Happy Hacking