>>6
Something to do and learn something different. I've already dealt with C, C++, C#, Java, Perl, Python, Ruby, and Shell. I do C/Perl/Shell at work, C# for my own OOP projects and Perl for scripts, Java at school, and have tried Ruby and Python in my own time.
Don't care for Lisp/Scheme's retarded parenthesis buttfuckery, so Haskell it is.