I end up doing a lot of diagramming and illustration work for the most of the training and support material I produce for clients. I’ve used Illustrator, FireWorks, and even PhotoShop in the past for some of this work. Each of these applications are powerful and feature-rich. But often they were overkill for what I needed.
These days I find myself turning more often to one very well-designed, easy-to-use application: OmniGraffle Pro