[jhancock]

Scala may get more mainstream traction. Haskell is good to learn if your also great at maths and can swing a job in elite financial circles. Erlang is certainly catching on. Can't speak for Clojure.

I learned Scala and erlang. Did a real world webapp with erlang 5 years ago before it was noticeably cool. Didn't me make any money aside from the one project (I chose the tech myself simply out of interest). Both scala and erlang helped me be a better programmer and renew my flagging interests. Other than that, I haven't seen any financial profits from it. I'm using ruby now simply because I have webapps to run and its the simplest way to get the job done.

Previous comments that people that learn these langs are putting themselves in better company are on target.