We have 2 boys (5 & 3) and a baby girl (2 months).
Obviously the girl goes to bed as and when she wants, although we are trying to get her in the same routine (by routine I mean night time order) as my boys, bath, milk, story, bed. And, again, she gets up when she wants.
On a weekday our boys have a bath at 7.30pm, milk, story and then bed at 8pm. They are woken up at 7am to get ready for school.
Friday & Saturday it is a little more relaxed. We still follow the same routine, but they usually go to bed at about 9pm. Saturday and Sunday they get up at around 9am, but are quite happy to play in their bedroom for half hour or so.