Sweating on a Web 2 Application

Have you asked yourself what is a good Web 2 application? What should it contain and what can be permitted to the users. I am working on a private configuration application, and I want to make it really useful for the users. Not just fancy picture sliding with JavaScript, in the matter of facts I don't have any pictures, but I have a lot of fancy JavaScript. My own opinion is that Java is the maturest language/technology for this kind of task. Java with Hibernate, Struts or maybe Spring. And of course JavaScript(give me a brake) for client scripting. JavaScript with JQuery, Mootools, Dojo or GWT. My personal liking goes for Mootools, but JQuery is a little more professional.