I love LISP, but alas I haven't done much in it. It feels a lot more intuitive than other languages.
It is also nice in that the language is what you want it to be. Very little of LISP is "standard", and you can easily change the language (via macros, which are supposedly very powerful in LISP), or by writing your own interpretor (I've heard that that isn't very hard).
You can also use any paradigm that you want. OOP, procedural, etc.