Just had to comment on a very useful new(ish) project for editing UML documents called UMLet. No frills or bs* just a good productivity tool in the open source space. Human readable file structure to enable old timers like me to hack in attributes with vi.
Converts your drawings to png, jpg, eps, pdf, svg, etc from inside the UI or even from the command line (a real programmer's tool).
It comes in two flavors 1) eclipse plugin, and 2) standalone Swing application. They have a few skins that help ease the swing pain but who cares about the L&F, I just want a tool that works with me instead of against me.
So, thanks to the UMLet team for a great product!