It really varies depending on week, project etc.
Normal hours 40 a week, with hours 8:30-5:30 but if I'm caught up can leave at 5 (normal legal secretary work week is 37.50 hours so if you work over it's not overtime).  If we have a project going I'm here until whenever finsihed.  Fortunately both my bosses have younger childrren and lots of soccer games!  None of my time is overtime, but it all balances out.  Very rarely do I take work home, I occassionally check my webmail, if I know I need to respond to someone.