Last month Pearson Education hosted a four day conference dedicated to GWT. For those who weren't able to attend (or even for those who were), the conference materials are now available, including:
In particular, you may want to check out Kelly's talk on usability, as well as Bruce and Dan's overview of how GWT can improve productivity. There's also the conversation with Josh Bloch and Joel's presentation on architecture design. And a panel of app developers talks about their firsthand experiences with GWT.
Thanks to Barbara Gavin and all the folks at Pearson Education for planning and hosting the conference. Thanks also to everyone who came to the conference for making it a success.