Expose is by far the most useful desktop command I have ever seen. Alt-tab, task-bar, workspaces, and everything else pales in comparison. Flicking the mouse to a corner and watching the windows shift gives much more utility than any other desktop organizational concept. And being able to shift everything out of the way to get to the desktop and open an item is icing on the cake. Unless you have used Expose for a week in a working environment, you have no idea how useful it is.
I wouldn’t even use it. I’ve been using icons (on a task bar or not) and alt-tab for more than a decade and a half. And the quick launch has a minimize everything button (which when you push it a second time does not put everything back, which really irritates me) so getting to the desktop is one click.
Like I said, it could be awesome but there is simply no way I’d use it, ever, not once. I already know how to do absolutely everything it can do quicker, and I’ve been doing them long enough that it’s instinctual so if I actually tried to use Expose it would take me longer.