[Axial]

I have Wacom Intuos 3 and it works beautifully with OmniGraffle 5, as well as with Apple's Keynote and the like. Of course, it does not support features such as pressure sensitivity and the eraser - this is something for which the drawing program itself should provide support - and I don't see how those would be particularly useful for Omnigraffle, anyway. Basically, it behaves like a mouse with absolute positioning. After a bit of practice, it becomes very fast to draw even complex diagrams with it. Make sure you get the newest drivers from Wacom's web site.