ok, i got this rather nice new laptop named latitude e6420 with rather ugly looks (e.g. that power brick is a joke) but awesome power (256gb samsung ssd, i5 2520M cpu, 4 gb memory, windows 7 pro 64bit), and the fact that for the first time ever a computer of mine does not produce any noise whatsoever is psychologically so above everything i experienced in the past,
but one thing i find totally unacceptable. i got the dock station where all my external hardware is hooked up to, like the second monitor, the external HDD, the printer and the Native Instruments sound card, and in balanced mode the computer seems to not be able to wake up its monitor when i come back to it after some hours of neglectance. everything seems to be "On" except of the screen (or screens; the external one doesn't wake up either), so i have to restart the system.
that is a nuisance beyond anything i could possily tolerate.
what you wrote helped me a lot finding out what caused the problem. i got an external usb soundcard (native instruments audio 2 dj, these days sold under the name traktor audio 2) connected to the dock. if that's plugged in, screen won't wake up from sleep, if it's disconnected no problem.
so i think i am gonna do what you wrote and just put it on hibernation instead of sleep when closing the lit. at the same time i have to make sure the energy settings are gonna do the same when the computer is on idle...