I need to produce several ERM, DMD and ORM diagrams for several projects I am working on. Obviously I'd like them to be a sleek and professional as possible, and while a simple Google search provides a plethora of options, they're all pay-for-use.
Are there any free (or open source) diagram creators available for Mac OSX which produce "sexy-enough" diagrams suitable and professional enough for use in client-accessible specification documents?
If you like latex, you might have a look at pgf. It generated the best looking chart I know, and the resulting files are very small.
But it does require a big learning curve and might not be what you are looking for.
How about Dia? It is designed to be similar to Visio, although slightly less business oriented. For Mac, you can get a Darwin Ports version or compile it from source, but this isn't always easy.
You should also check this other SO thread.