Shortcuts to use during system startup:
X = Force your Mac to startup
Option-Command-Shift-Delete = Boot from a secondary drive, such as CD or floppy.
C = Boot from CD
N = Boot from a network server
T = Boot in Firewire target disk mode
Shift = Boot in safe mode
Command-V = Boot in Verbose mode
Command-S = Boot in Single User mode
Shortcuts to use with the Finder window:
Command-W = Close window
Option-Command-W = Close all windows
Command-Right Arrow = Expand folder in list view
Option-Command-Right Arrow = Expand folder and nested subfolders in list view
Command-Left Arrow = Collapse folder in list view
Option-Command-Up Arrow = Open parent folder and close current window
Shortcuts to use with the Apple Menu:
Shift-Command-Q = Log out
Shift-Option-Command-Q = Log out instantly