The process of writing large parallel programs is complicated by the need to specify both the parallel behaviour of the program and the algorithm that is to be used to compute its result.
What should you learn first, Lisp or Haskell? It depends entirely on your personality. One thing is certain - if you want to be a great developer eventually you'll have to learn both.
P. Hudak, J. Hughes, S. Jones, and P. Wadler. Proceedings of the third ACM SIGPLAN conference on History of programming languages, New York, NY, USA, ACM, (2007)