I am an insomniac. When I don't have work, I'm usually not up till almost noon. At Disney I force myself to get up early. I wake up, slap myself a few times, go for a quick run, and shower. I'm still the walking dead afterwards at the rope drop. When I finally get around to having coffee (I wait till in the park to avoid the Nescafe in the food courts) I perk up. I'm willing to make the sacrifice though. It just really makes the whole day much easier when you knock out all of the big rides early on.
If we go to a park twice, we do one day getting there at rope drop and the other day we sleep in and show up around 10/11. I'm on vacation, I need to sleep in at some point.