"Visio" is most probably the application that comes to your or anybody else's mind first when being asked about a diagramming software. Not many know that there is a great and powerful program available for free that does a very good job in that area as well. In fact, I prefer it over others for its great auto arrange capabilities.
yEd by yWorks is a great example for a "free but professional" application. It is as simple as it is feature rich. It comes with several icon libraries and diagram templates and I am sure that anyone in need of a diagram or flowchart will be able to create it with yEd (BPMN diagrams, Flowcharts, Family Trees, Semantic Networks, Social Networks, UML Classes, Org Charts, Network diagrams, Swim Lanes and more).
What I liked about yEd is its great capability to auto-arrange your diagram. Don't worry about the layout too much while creating your flowchart. Just add your boxes and connections and then when you're done, use one of yEd's many auto-arrange algorithms. I am confident you'll find one that does it just right for you.
yEd is freely available and runs on all major platforms: Windows, Unix/Linux, and Mac OS. Get it here:
This article is maintained by George