I suppose this is a strange question to the huge majority of programmers that work daily with Java. I don't. I know Java-the-language, because I worked on Java projects, but not Java-the-world. I never made a web app from scratch in Java. If I have to do it with Python, Ruby, I know where to go (Django or Rails), but if I want to make a web application in Clojure, not because I'm forced to live in a Java world, but because I like the language and I want to give it a try, what libraries and frameworks should I use?
By far the best Clojure web framework I have yet encountered is Compojure: http://github.com/weavejester/compojure/tree/master
It's small but powerful, and has beautifully elegant syntax. (It uses Jetty under the hood, but it hides the Servlet API from you unless you want it, which won't be often). Go look at the README at that URL, then download a snapshot and start playing.