If you haven’t already checked out the restlet project then it’s definitely worth a gander. It is a lightweight framework that captures the principles of REST as outlined in Roy Fielding’s dissertation. For me the REST architectural style is the superior choice for all client facing web applications.
The restlet framework comes packaged with everything you need to develop the server and client dimensions of your web applications although in my instance i was more interested in integrating it with Spring 2.0 and the Tomcat Servlet Container.
Initial experience with the framework has been both positive and beneficial.