LISP was (and is) used for a lot more than AI. Some of the most advanced software in the world uses LISP, even today. Here's an account of LISP being used for something we may all be familiar with: e-commerce web-sites:
Beating the Averages
Clojure is an modern LISP with several distinct advantages - it runs on the JVM (which gives it instant access to thousands of battle-tested libraries and frameworks), it is functional (which means core data-structures are immutable), and has support for multi-core concurrency (with an elegant implementation of software transactional memory or STM).
Each of these features makes it really powerful in the hands of a skillful user. Being a LISP, it also has complete support for Macros, which is a
secret weapon in its own right.
These are just some of the reasons why it's worth learning and using Clojure. My own startup,
Runa, is an all-Clojure shop. We've built some incredibly powerful software with a team of just 5 engineers. There are a lot of similar success stories. Also, the Clojure community is amazingly friendly and helpful!