One of the things I don't like about Haskell is that it has a really complicated type system because it isn't (and couldn't realistically become) dependently typed. This is one of the things that drew me to lisp, you can choose which type system you use.

I must disagree with you on purity though. Purity allows you to apply equational reasoning, it allows compilers to apply optimizations that wouldn't otherwise be possible. It makes multi-threading, if not possible then substantially easier. You do get some of these advantages from having purity by default, but if it's not enforced, you can't get most of them. For me, I see this as an acceptable compromise (actually I don't see it as a compromise at all, if all I got from purity was equational reasoning I'd still use it), but as you point out, the culture amongst lispers is different.

Thanks for the book recommendation, I must admit that I already have a number of books to get through before I'll be able to look into it (including LiSP and "Compiling with continuations"), but I surely will do.