SmartGWT and GWT 2.1 some notes
There are several libraries for GWT; SmartGWT is one of the riches and powerful (showcase )
Although I used their visual components I prefer using the GWT core components. Specially the new version 2.1 M3 which include Data Presentation Widgets (CellWidgets) that enables you among other create “real” tables with headers footers pagers (e.g. gwt-bikeshed , CwCellTable-Showcase,).
I have put number of links which discuss the SmartGWT and other GWT libraries :