We're in an early stage of a new web project. The project will grow and become complex over time. From the beginning we will have unit and integration tests using JUnit and system tests using HtmlUnit. We might also add some static code analysis tools to the build process if they prove to be of value to us.
If you're or have been involved in a project which uses continuous integration. Which software do/did you use and do you think it has payed off? Which software would you recommend for continuous integration of a Java web project?