The Electronic Frontier Foundation (an organization I am happy to plug. They do wonderful things.) has just released a joint report, along with some of Princeton's best technology brainiacs, to announce they've found a serious security vulnerability in laptops when they are in that nether world between on and off.
This applies to both Microsoft and Apple's disc encryption programs like BitLocker and FileLocker respectively.
Researchers have found that encryption keys and passwords stored in RAM, home of the computer's short-term memory, tend to linger for awhile even after losing power or going into sleep mode. This allows hackers a window of opportunity to exploit your data's security.
Many notebooks go into sleep mode by merely flipping down the screen, a common move for the worker bee parked at Starbucks wanting to hop up to grab a latte without completely shutting down. If this means you, next time take the time and shut down.
File this under "what a pain". This is just another reason that I can't wait for the operating system to move to a flash drive and speed up booting up.