Don't be too quick to dump your plugin or applet based portions of your application. While ajax and dhtml can do drag and drop and other advanced user interfaces there still limitations especially when it comes to browser support. Plugins and applets have been around for a while and have been able to make ajax like requests for years. Applets provide a great set of ui components and apis that provide developers literally anything.
What are the properties of xmlhttprequest?
What are all the features of Ajax?
What does json stand for?
What is the role of the scriptmanagerproxy control? : asp.net ajax
Explain Ajax polling?
What are asp.net ajax 4.0 validation controls?
What are the benefits of ajax over java applet?
How can we handle exception handling in Ajax?
What are the basic controls in asp.net ajax?
What does the dynamicpopulateextender control do? : asp.net ajax
Can I use ajax with seam?
Does ajax have significant accessibility or browser compatibility limitations? Do ajax applications break the back button? Is ajax compatible with rest? Are there security considerations with ajax dev