Lots of good programming languages out there, but I doubt we'll ever get one with the elegance and simplicity of #Lisp (I bucket here all derivates like #Clojure as well).
Sadly, most other languages suffer from an ever growing syntax complexity. Many people call the syntax of a language like #Python “simple”, but I think they actually mean it's "familiar” / “sensible" to most programmers and non-programmers. Simplicity and familiarity are two pretty different concepts, though.
Which languages do you like/favor for their simplicity?