One more thing that you may or may not know is that functional programming languages are a kind of fuzzy concept. There are at least two different categories (well, probably it's more a continuum, but ..), being functional programming languages vs. function-level programming languages. (Note: Someone please correct me, if I'm confusing the terms here). Lisp's belongs in the first category, where Haskell probably belongs in the latter. The first category is more similar to main stream, procedural languages, where the latter is more abstract. Which is a better choice is open for debate; On the one hand, you'll probably grasp Lisp faster than Haskell, on the other hand you might end up writing procedural code in it, instead of function oriented code.

See: http://en.wikipedia.org/wiki/Function-level_programming#Cont...