I programmed in Lisp professionally for about a year, and it is definitely worth learning. You will have unparalleled opportunity to remove redundancy from your code, by being able to replace all boilerplate code with functions where possible, and macros where not. You will also be able to access unparalleled flexibility at runtime, translating freely between code and data. Thus, situations where user actions can trigger the need to build complex structures dynamically is where Lisp truly shines. Popular airline flight schedulers are written in Lisp, and there is also a lot of CAD/CAM in Lisp.
