Sleep command/switch logic on Macbooks

dorayme wrote on :

Is there is any iron logic to sleep for Macbooks or does it sort of go with the weather?

13" late 2009 Macbook connected to an LCD screen, a usb tethered keyboard (irrelevant as it happens) and a bluetooth mouse, latest Snow Leopard, and both screens forming one desktop, (the MB screen usually turned down to zero)

If I log out and mouse over the sleep in the login window, it sleeps. But it invariably is a light sleep and wakes a few secs later. I do it again and it sleeps then. But, like an afternoon nap, it is deep and dreamy but wakes in about 10 or 15 minutes.

I am only confident of it going to sleep and staying asleep when logged out if I close the lid to put it to sleep.

If I am logged in, it stays asleep after Command Option Eject until a key is hit or a usb device is inserted or pulled out (I think the latter is right).