Got AJAXed ? I didn’t. Yet, maybe…. To me it seems clumsy to build, unstable because of its environment, load-increasing (on the serverside) and after all, a damn lousy copy of a realclient gui. No need to compare that Java/SWT GUIs that are (few people tend to forget that) available through the browser too but (when using webstart instead of applets) damn stable, cleaner to build, near to the l&f of the OS and – compared to AJAX – blazing fast.
If you’re still interested in AJAX, well
ajaxpatterns.org might be an interesting resource for you.