In response to Results of the 2012 State of Clojure Survey:
The idea of having a primary language honestly comes off to me as a sign that the developer hasn't spent much time programming yet: the real world has so many languages in it, and many times the practical choice is constrained by that of the platform or existing code to interoperate with.
I’ve been writing code for ~18 years, ~10 professionally. I’ve programmed in (chronological order here) Modula-2, C, Basic, the HTML constellation, Perl, XSLT, Ruby, PHP, Java, Mathematica, Prolog, C++, Python, ML, Erlang, Haskell, Clojure, and Scala. I can state unambiguously that Clojure is my primary language: it is the most powerful, the most fun, and has the fewest tradeoffs.
Like Haskell, I view Clojure as an apex language: the best confluence of software ideas towards a unified goal. Where Haskell excels at lazy, pure, strongly typed problems, Clojure is my first choice for dynamic, high-level, general-purpose programming. I wish it were faster, that it had a smarter compiler, that it had CPAN’s breadth, that its error messages were less malevolent, that it had a strong type system for some problems. But for all this, you gain a fantastically expressive, concise, rich language built out of strikingly few ideas which lock together beautifully. It gives you a modern build system, a REPL, hot code reloading, hierarchies, parametric polymorphism, protocols, namespaces, immediate, lazy, logical, object-oriented, and functional modes, rich primitives, expressive syntax, immutable and mutable containers, many kinds of concurrency, thoughtful Java integration, hygenic and anaphoric macros, and homoiconicity.
Were Clojure to cease, I would immediately endeavor to replicate its strengths in another language. That’s a primary language to me. ;-)