If you are looking for J2EE support then I would strongly suggest you take a look at NetBeans 4.1. It has excellent support for EJBs, JSP, and Servlets built right in. No need to go looking for a plugin.
Hi If you want to use special features of an (Eclipse here) IDE for developing JSP and ejb then you should install some plugin for it because Eclipse out of the box has no support for EJB / JSP Eclipse need web tool plugin wich has not released yet -AFAIK But there are other commerical plugin like www.myeclipseide.com for 29.9 a year. -I think-
But you have another IDE named Netbeans , with "out of the box" support indeed very good support of developing J2ee application . it hase JSP ,WS ,EJB developing helpers wich you can use them along with other IDE features.