I think your short answer deserved a ++ in itself.

I have considered learning Python and Ruby for a while and intend to do it as soon as my projects let me relax a little (which may as well mean never). Learning something is generally good and Python has its merits. Once you know it, you might either decide that it's better than Perl at some tasks, or borrow idioms and techniques into your Perl programming practices. You might also decide it's not worth much effort and offer people detailed reasons why.

I recently started programming in Java and even if some tasks are made infinitely tedious, the way the language is designed gave me a better insight on software design and programming techniques. Now my OO-design is a bit more careful and my Perl code a bit cleaner. And even if Perl remains my favourite language, for any new project I consider using Java and sometimes decide it's a better choice for the task at hand. Furthermore, during a talk I gave recently I could use it as a benchmark to show Perl's effectiveness at string and template handling ;-).