You couldn't pay me to use an existing desktop mail client over Gmail, either. Other than reasons you already iterated, the killer feature for me, the one I tr

You couldn't pay me to use an existing desktop mail client over Gmail, either. Other than reasons you already iterated, the killer feature for me, the one I truly cannot be without, is the threaded conversation view. I know some desktop clients have threaded views, but unlike Gmail's implementation, they suck.