yEd - It's not Visio alternative, it's better. |
I was recently looking for Visio alternatives on Linux and while Dia is good it lacks the oomph of Visio and hence not an easy sell for new and potential Linux converts.
Now good news for those open to enter the wonderful world of Linux is that any OS need not have an alternative for it to be usable to you, all it needs is the ability to let you run the software you find useful.