There has been a spate of interest in Windows Vista's convoluted shutdown process started by this Joel on Software post. Fuel was added to the fire when Moishe Lettvin blogged about the design process that was involved with the 'shutdown feature.' The short version: lots of people, lots of meetings, and very little actual code was involved.
We can compare Microsoft's process with Apple's thanks to this post by Arno Gourdol, formerly lead of the Mac OS X Finder team. Not too surprising Apple's process was much more straightforward and involved less people. However, lest you think that all is roses and candy corn in Cupertino, one Apple exec insisted that the 'Log Out' function should have a keyboard shortcut. Not a horrible idea, right? How about if I told you the key combo that exec wanted to use was Cmd + Q? I can imagine many people trying to quit an app and logging out instead. Luckily, cooler heads prevailed and Shift + Cmd + Q was the chosen one.