Stand-alone charts in GWT

Question

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 messy to control (it seems buggy, in general).

I'd like to hear about something that works with the least amount of dependencies and it also must work without a connection to the web (so, Google' charts API isn't a solution).

Edit: Indeed, I would rather a library that is all client-side.