I\'ve been trying to get pretty charts to work in GWT on our internal network.
Playing around with GWT-Ext\'s charts is nice, but it requires flash and is really mes
+1 flot, requires jQuery though, so might not play well with GWT, I haven't used that.
If you're looking for client-side check out flotr which is based on prototype javascript library or flot which is based on jQuery. Both work well, though flot seems like its got a bigger backing.
Googling for "GWT +sparklines" has gotten me to gchart, which seems like what I need.
From what I understand - it's all client side and requires nothing more than their JAR file.
Do you want something that has a server side component or entirely client driven? The best ones I have seen are all flash, alas. I have done little tricks with JS and GWT before, but there is only sophisticated I will get before I go hunting for a library to do it for me.
gchart looks seriously awesome. Go with it !
There is also "sparklines" - they are available in lots of flavours (very simple charts though).