Netbook/laptop + OS: Shortest time to action?

When I wake up during the middle of the night I want to be able to, as quickly as possible, start writing things down least I forget them. Which netbook or laptop combo would go from a state of complete silence (no buzzing fans etc.) to a working state in the shortest amount of time? It can be from power off, hibernation, suspension or whatever you call it as long as it’s completely quiet.