@Dr Herbie:"on a new Win7 install, the start menu orb is the only control on the taskbar and therefore draws the users attention to click it"
No it isn't. Starting from the left of a new install of Win7 there's the Windows orb, IE, Explorer and Media Player icons, and if I'd never seen Windows before I'd probably try clicking the Media Player icon first (it's got a big "Play" arrow next to it), the Windows orb mostly looks like a badge logo. Assuming I'd tried all the icons and found Start, if the Start men's suspend button is set to sleep what discoverable feature tells me the right-pointing arrow is "shutdown"?
"Win8 hides the shutdown option beneath 2 layers, making it less discoverable."
It "hides" the "shutdown while logged in" option in the "settings" menu sure, but the shutdown option is also in the sign in screen pretty clearly.