OmniGraffle Pro is very cool
I used OmniGraffle 3 Professional this week to draw up some state diagrams for some tricky web UI I was working on. I've used OmniGraffle 1 and 2 in the past to do these, but hadn't used OmniGraffle 3 yet. I decided to try it out since they have free trial licenses on their site.
W-O-W. I was sold before I even downloading it, just looking at the pro page and the samples page. Then I used it. I got that feeling I get whenever I use a truly killer app for the first time. Giddyness, mostly.
State machine written, UI working... and documented with state diagrams. :-)