Other Ajax oriented GUI Toolkit
Plex Toolkit
An XML+Javascript based toolkit that aims developer to make up very amazing interfaces, creating interface in XML format. Can find demo here.
QooXDoo
QooXDoo is an advanced open-source JavaScript-based GUI toolkit. QooXDoo continues where simple HTML is not enough. This way qooxdoo can help you implement your AJAX-enhanced web 2.0 application - easier than ever before.
QooXDoo also seems to be a very interesting JS Framework to make up beauty interfaces. Demo here.
Ok, everything beauty, amazing, interesting, powerfull… bla bla bla. But, using JavaScript!!! The terrible-ungrammaticated-unportable language trapped in out browsers.
I think that in the future only “complete” solutions as GWT, that aims to write EXCLUSIVELLY Java Code, autogenerating JS code, becomes the MUST for Web-Apps development.