Personally I've tried Python, Ruby, Pascal, Basic, C++, Java and Assembly.
Of those languages I would probably recommend C++ since it's relatively easy to learn and is very widely used in the entire software industry. Java can be slightly easier to learn, but also has a lot of limitations and isn't nearly as powerful.
I have a friend who mostly uses C# and according to him it's a lot like C++ but is an evolved version of it. So I'd guess that C# is a bit harder but is more powerful than C++. C#, if I'm not mistaken, was developed by Microsoft, and probably works better with Windows than any other OS.
Pascal and Basic aren't really used much any more since they're both very old and outdated. They are both very simple.
Ruby and Python aren't used much for actual programming, they are more common as scripting languages. But they can be quite easy to learn.
Don't even bother with Assembly, as it is used to program microcontrollers and microprocessors, and has pretty much no use in the software industry.