Great idea, although I hope it's better than the power saving in Windows7. If I leave my PC on the default power management settings then it invariably decides to put itself to sleep at unfortunate times - like halfway through a virus scan.
This time around it's Microsoft's announcement that its goal is to suspend Metro apps that are currently not visible on the screen
Hmm, if it does that isn't there the possibility that it's going to suspend a long running process that you've iconised purely so you can get on with some low cpu task while the other is running?