Its an excellent video that lists down many interesting things: A must watch for UI archs.
Just to summarize few of the architecture points discussed in this (and my comments)
1. MVP pattern usage in GWT. (using gwt-presenter library probably) http://martinfowler.com/eaaDev/uiArchs.html
2. Dependency injection on client side (Google-gin (client-side) and Google-Guice(server side))
3. Event Bus (following event collaboration by martin fowler http://martinfowler.com/eaaDev/EventCollaboration.html)
4. Command Pattern (probably using gwt-dispatch)
Hope it helps.. Please share your understandings as well.