I have used many different wire framing applications over the years. I was never a huge fan of Visio, tried Balsamiq Mockups and even dabbled in using Adobe Illustrator to perform my duties.
I have found that OmniGraffle along with the myriad of stencils from GraffleTopia has proven to be the perfect tool for what I do on a daily basis.
Now that I can spend a majority of my time developing better experiences for clients on our platform (when I am not in meetings), I enjoy this robust tool that can facilitate the development of flow charts, wire frames and any other necessary high-level experiences necessary to communicate my message.
GraffleTopia includes jQuery Mobile elements as well as traditional flowchart, organizational and common desktop elements just to name a small few stencils.