grafwiz

I use it too but I wouldn't mind a non-ugly layout renderer!

Not sure what gliffy is but Graphviz can conceptually draw the same thing. You can have box shapes and colors for nodes and edges both. However, the rendering layout itself is usually unpleasant. You can have some control but it's really suboptimal. As I said, Graphviz is both simple and very powerful so no reason to not use it to represent data in concept. Plus it goes in your VCS.

This is beautiful that's it but this is nothing considered to graphviz. If Graphviz had a decent, just non-ugly renderer it would be much more popular.

Eg. Mind maps aren't trees- they are bigraphs, this is limited to trees.

Someone needs to plug in this renderer with Graphviz.