The laptop I use has the F8-F10 keys given over for controlling the keyboard backlight, so those aren't useable for expose. I currently have the expose and dashboard functions mapped to F11 and F12, ...
Accept video call = Ctrl + Shift + A Accept audio call = Ctrl + Shift + S Decline call = Ctrl + Shift + D Start audio call = Ctrl + Shift + C Start video call = Ctrl + Shift + U Toggle mute = Ctrl + ...