Varies.
Last night I got back from the pub about 12, had a few more beers, watched telly, ate leftover curry. Got to bed around 2, got up at 6, got showered, went to the cafe, went to work.
All I can say is I had a good night but i'm tired.
But it does vary, sometimes I go to bed about 10/11.
The more sleep I get, the worse I feel in the morning, I wake up after a 10 hour sleep i feel like i've been beaten up for about 2 hours afterwards. But I get a 6-8 hour sleep i'll feel pretty rough for a while. The toruble with less sleep is I get less drag in the first few hours of my day but more later on. It's a delicate balance which I had decided to ignore. If I didn't have an alarm clock I wouldn't wake up til about 12.