OmniGraffle is one of the best reasons to get a Mac — think of Visio, only without the overhead it acquired in the last few releases, and done by designers who really know how to build a beautiful Mac UI. Graffletopia contains a huge selection of stencils (“shapes”).
This is a single archived entry from Stefan Tilkov’s blog. For more up-to-date content, check out my author page at INNOQ, which has more information about me and also contains a list of published talks, podcasts, and articles. Or you can check out the full archive.