[pablissimo]

I know it's not wholly functional, but a lot of programmers who are used to all-procedural programming struggle to adapt to anything functional. I've used Lisp for AI stuff before and toyed with Scheme from an academic-interest point of view and it's great fun once you get yourself into how Lisp operates. A lot of my problem was that I had in my head that it was more complicated than it was, and tended to create problems for myself when none existed.

If you like Lisp you should have a look at OCaml for comparison. There are a lot of very smart people writing obscenely functional (in the 'things it can do') code with very little effort for both languages.