Are there any good themes or component libraries for GWT? The built-in themes are rather plain for my purposes. I've seen gwt-ext and smartgwt, but those aren't that great looking. Are there any others that have a real nice look? I know of vaadin an I really really like the look, but from what I understand that just an entirely new framework.
The first thing to be careful of is that there are two frameworks which use EXT and GWT:
Both are based on the Ext JS component library.
Gwt-Ext is based on an old version of Ext JS when it was still LGPL but is no longer developed.
Ext GWT is from the same company who are still developing Ext JS. It's still being developed and is available under free and commercial licenses, and of the two is the one I would use.
SmartGWT is an alternative (and is what the GWT-Ext people are moving to). A colleague of mine looked at it and did not like it as much as Ext GWT as it's a fairly thin wrapper around the SmartClient JavaScript whereas Ext GWT has quite a lot of Java code. The difference being that if you run an Ext GWT application in Hosted Mode and attach your debugger you can see what Ext GWT is doing, but with SmartGWT you'll just see lots of IDispatch calls where it disappears into native JavaScript where your debugger won't be able to follow.