What Programming Languages Should You Learn Next?

simoniker writes "Over at Dobbs Code Talk, Chris Diggins has been discussing programming languages beyond C++ or Java, suggesting options such as Ruby ('does a great job of showing how powerful a dynamic language can be, and leverages powerful ideas from Smalltalk, Perl, and Lisp') but suggesting Scala as a first choice ('Very accessible to programmers from different backgrounds.') What would your choice be for programmers extending beyond their normal boundaries?"