Presentation Layer
A J2EE project usually has some form of web component to it. Although this is not strictly necessary, it is very common. I have seen a number of projects in which great care was taken to design the Entity Beans, the Session Beans, and the Message Beans, but when it came to the presentation layer, it was just thrown together with hard coded JSPs and clunky servlets.
If your project will have a web presentation layer, some form of library should be used other than just JSPs and Servlets. For this layer, I also turn to Open Source and use Apache’s Struts. They combine very nicely with XDoclet and provide a very clean workflow that can be adjusted as needed.
There are a number of web presentation layers available that sit on top of JSPs. Although I prefer Struts in the projects I am working on, there are many very good options out there. If a majority of your team is comfortable with a particular library, that previous experience will outweigh most differences between the most successful libraries.