F9 miniaturizes all the windows open in all applications so you can pick the one you want right now (a godsend for someone like me who keeps 7 apps running more or less continously and often has upwards of a dozen tasks going per app). F11 clears everything off the desktop and then brings it all back on the second tap. Those two tools plus the taskbar are necessary for someone like me who bounces between tasks more or less continuously.