Here's a tip - I do a lot of development on other J2EE platforms, noteably IBM WebSphere. The problem I run into constantly is the size of the server, how long it takes to restart, and having enough memory to run a development environment AND the J2EE server. Tomcat solves all that for me. I develop under Tomcat and then port to WebSphere in the last week of the project. Wonderful!
My only concern with Apache/TomCat/JBoss is bugs. Anybody know if the bugs are big problem for the development ? I currently use JRun which is quite stable. Although it has bugs, it is quite reliable .