I've noticed that my iMac display is not sleeping after x amount of minutes (as set in the Energy Savings preference). What will happen is it will turn off, then half a second later, turn back on. When I do ctrl + shift + eject the display sleeps fine. Things I've tried: restarting, repairing disk permissions, resetting PRAM, and resetting the SMC. Did a search for other options, didn't find anything I haven't already done. I can't think of anything that changed recently, other than turning screen savers off (which, come to think of it, also never seemed to work properly), and we lost power at some point this week (though I'm fairly certain the issue existed before that). I'm running a 2011 iMac on Snow Leopard. Any help would be really appreciated.