Haskell at the top of the list was one that I really enjoyed. It has a pretty scary learning curve but its wonderful having a language that feels so consistent.
I disagree. I think a lot of uninitiated potential haskell users are turned off by hearing about the "scary" learning curve. The key is to forget everything you know about imperative programming going in. There's a temptation to compare each Haskell idea with the similar idea in whatever language(s) you already know. Approaching with an open mind turns that "scary" learning curve into an easy and rewarding journey.
The scary learning curve isn't really a bad thing, I was never turned off by it, the main turn off for any programming language for me is going to be resources which is why I chose python over ruby (as python has in my opinion much better documentation and community).
As a disclaimer I've never really learned haskell yet, I do go through tutorials and solve some problems with it and everything now and again but I haven't fully grokked the language yet.
