There's some memories I have, mostly applicable to text/terminal applications... that productivity generally falls off when you have more than a dozen or so actions on the screen at a time. That people are usually better off with sub-menus or other contextual menus over too many options.

I find the UX for GMail, for example to be particularly good, not perfect but very very good for the task. The biggest issue I have with gmail is really folder and rule management.