UPDATE: Oct 20, 2012:  Turn the Windows 8 Start Button back on which includes the power options: urtech.ca/2012/10/solved-solved-solved-oh-joy-solved-how-to-add-the-start-button-into-windows-8 

ORIGINAL POST BELOW:
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Like older versions of Windows, Windows 8 has a built in SHUTDOWN executable, which means you can easily create your own icons and add them to your Quick Launch bar or the pin them to your Taskbar.  All the details of which you can see at the bottom of this post.

The interesting news is that Windows 8 offers a /HYBRID shutdown, which closes and kills everything BUT Windows 8 kernel and drivers.  This means your HIBERFIL.SYS will be much smaller and Windows will boot WAAAAAY faster.  So I suggest you make a nice shortcut that looks something like:

shutdown.exe -s -hybrid -f -t 0

This means shut down in hybrid mode, force everything to close and don’t wait.

Below are all my shortcuts. 

Click here to download Windows 8 SHUTDOWN Shortcuts.

The only odd one is SLEEP with uses:

 rundll32.exe powrprof.dll,SetSuspendState Sleep

.

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C:\Windows\system32>shutdown.exe
Usage: shutdown [/i | /l | /s | /r | /g | /a | /p | /h | /e | /o] [/hybrid] [/f]

    [/m \\computer][/t xxx][/d [p|u:]xx:yy [/c "comment"]]

    No args    Display help. This is the same as typing /?.
    /?         Display help. This is the same as not typing any options.
    /i         Display the graphical user interface (GUI).       This must be the first option.
    /l         Log off. This cannot be used with /m or /d options.
    /s         Shutdown the computer.
    /r         Full shutdown and restart the computer.
    /g         Full shutdown and restart the computer. After the system is rebooted, restart any registered applications.
    /a         Abort a system shutdown.   This can only be used during the time-out period.
    /p         Turn off the local computer with no time-out or warning.  Can be used with /d and /f options.
    /h         Hibernate the local computer.  Can be used with the /f option.
    /hybrid    Performs a shutdown of the computer and prepares it for fast startup.   Must be used with /s option.
    /e         Document the reason for an unexpected shutdown of a computer.
    /o         Go to the advanced boot options menu and restart the computer.    Must be used with /r option.
    /m \\computer Specify the target computer.
    /t xxx     Set the time-out period before shutdown to xxx seconds.
               The valid range is 0-315360000 (10 years), with a default of 30.
               If the timeout period is greater than 0, the /f parameter is  implied.
    /c “comment” Comment on the reason for the restart or shutdown.  Maximum of 512 characters allowed.
    /f         Force running applications to close without forewarning users.
               The /f parameter is implied when a value greater than 0 is specified for the /t parameter.
    /d [p|u:]xx:yy  Provide the reason for the restart or shutdown.
               p indicates that the restart or shutdown is planned.
               u indicates that the reason is user defined.
               If neither p nor u is specified the restart or shutdown is unplanned.
               xx is the major reason number (positive integer less than 256).
               yy is the minor reason number (positive integer less than 65536).