I'm kind of a night owl, lights out at 11-11:30 and up at six. If I didn't have to get up in the morning, I'd probably never go to bed before 1 am. However, my middle schooler goes to bed at nine. He needs to sleep. Parents who let their kids stay up to midnight aren't doing them any favors. My guy is occassionally allowed coffee, not much, not often. I really don't mind the coffee as much as soda/pop, which some kids seem to drink by the gallon. I lived in Europe for awhile and kids there drink coffee or tea from a very young age, but almost never drink soda. They seem to do fine to me.
