This post has been a long time coming, so apologies to those who have been anticipating it for some time. Some background: at Usability Matters we spend a large part of our time wireframing. When we were on Windows machines, we used Microsoft Visio for this, but we switched to Macs in the fall, are now using Omnigraffle to wireframe. Both Visio and Omnigraffle are extremely powerful tools, but they are both pretty pi