The reliable purely functional programming language.
Advanced type system makes it possible to eliminate the wide class of bugs at compile-time. The pure nature allows to build parallel and concurrent programs much easier than in other languages.
Haskell compiler can produce either native code or LLVM code of your choice. Its performance is at least on par with the fastest languages with garbage collection runtime.
Haskell is incredibly productive and incredibly fun. It relies on mathematical foundations, allowing you to create incredibly powerful abstractions when needed.