I'm new to Macs, so forgive me. With the default settings, will the new MB (I have the 2.0Ghz) fully "Sleep" when you close the lid? What about, when you leave it open and walk away for hours? I left the default settings for when the screen darkens and HDD turns off. The reason I ask is that even if I close the lid, overnight my Macbook battery life will deplete COMPLETELY. I have left all the settings as default and it seems to not matter if I close the lid or not. Tonight I'll do an experiment and manually put it into sleep and see what happens.