If you are dissappointed that Microsoft seems to have left out some basic tools in SCCM, download and install this free add-in:

http://myitforum.com/cs2/blogs/rhouchins/archive/2008/04/09/sccm-right-click-tools.aspx

One of the more basic items that it offers is the ability to shutdown or reboot a system through a simple right-click menu.

I also ran across this nice collection of tools for SCCM:

http://www.myitforum.com/myitwiki/SCCMTools.ashx