I usually go to bed 8 hours before my alarm goes off, though I'm aware that it takes me an hour or more to drop off (so I've voted 7 hours). At weekends I'll usually sleep 8-10 hours (no alarm).

I've always been a terrible sleeper, unable to get to sleep, and unable to get out of bed in the morning. I've got my night-time rituals, dark, quiet room, reading before bed, regular wake-up time, but none of that seems to help, some nights I'll hear my room mate getting up at 5 before I fall asleep.