Which is the best implementation of LISP family of languages for real world programming ?

[tfgordon]

Consider Clojure:  http://clojure.org/

You might want to watch one of these videos for an overview:

http://clojure.blip.tv/

There is also evidence that Clojure is currently the most popular
Lisp, more "popular" than Scheme or Common Lisp, whatever that means:

http://www.google.com/trends?q=common+lisp,+scheme+language,+clojure

-Tom G.