Let's imagine for a second that we live in a world where all programming languages are equally suited for any task. Performance, memory footprint, compile time, executable/runtime size and compatibility, and similar factors are entirely irrelevant. Valid criteria could be personal taste, perceived elegance and beauty of the language, simplicity, easiness to use, and so forth.

If any programming language could fulfill equally well the requirements for any application/system and run anywhere, which language would you like to see everything written in?

My personal choice would be Lisp. I think Lisp is beautifully simple, there are very few syntactical constructs, it's easy to extend with macros and very suitable for functional programming.