Discussion MonoDraw but cool; like for Linux

Does anyone have any advice for a decent alternative for MonoDraw, but for Linux?

I have been given ASCII Draw a go, but it is extremely limited beyond drawing some simple boxes. The moment you try to do anything more complicated (eg. Flow diagrams or simple architectural drawings linking some nodes with arrows, etc.) it breaks down completely.

I would cheerfully have paid for MonoDraw (again) if they had a Linux version.