Programming Languages and Taco Bell: Same Features, New Combinations

Except that unless you're unusually awesome, you don't generally express your ideas by means of chalupas.

But seriously. Diversity in language design, in the implementation of new languages, and even in the extension of currently popular languages, is a good thing (TM). It means being able to learn a new approach or technique (anonymous functions, monads, templates, erlang-esque pattern matching, etc) and be able to integrate it into the projects you've already spent 5 years of your life on.

(edit: missing comma)