What are the essential Clojure libraries to learn beyond the basics of “core”

Question

I am teaching myself Clojure. I've started using Leiningen, I'm working on Clojure Koans, plan to do LabREPL next, and will have a look at Noir.

My question is: what are the essential "must know" Clojure libraries and functions to know beyond those covered in the above learning plan?

Looking at Clojure Contrib, there are large number of libraries. As a professional (or OSS) Clojure developer, which do you find yourself using on a daily basis? Which ones are not so useful or otherwise not commonly used (i.e. are esoteric / do not come up often in day-to-day coding).

Answer 1

That is really depends on your domain and on what you going to code.
Avout brings Clojure state to the distributed world.
And Lojic brings logic programming to Clojure programming language, it is an interesting project.
Cascalog for example is a Clojure-based query language for Hadoop, amazing thing if you are going to do Hadoop programming.
FleetDB is a schema free database written in Clojure.

So it is really based on what you are doing.

(Ok, my answer covers the first section of your question).

My list of most used contribs: clojure.contrib.accumulators, clojure.contrib.duck-streams, clojure.contrib.lazy-xml and clojure.contrib.zip-filter.
Those are essential to me, YMMV.