Possible Duplicates:
Why is Lisp useful?
Is LISP still useful in today's world? Which version is most used?

First of all, let me clarify: I'm aware of Lisp's place in history, as well as in education. I'm asking about its place in practical application, as of 2011.

The question is: What features of Lisp make it the preferred choice for projects today? It's widely used in various AI areas as far as I know, and probably also elsewhere.

I can imagine projects choosing, for instance...

• Python because of its concise, readable syntax and it being dynamic,
• Haskell for being pure functional with a powerful type system,
• Matlab/Octave for the focus on numerics and big standard libraries,

Etc.

When should I consider Lisp the proper language for a given problem? What language features make it the preferred choice then? Is its "purity and generality" an advantage which makes it a better choice for some subset of projects than the modern languages?

edit-> On your demand, a little rephrase (or simply a tl;dr) to make this more specific:

a) What problems are solvable with Lisp much more easily than with more common, modern languages like Python or C# (or even F# or Scala)?

b) What language features specific for Lisp make it the best choice for those problems?