This will also depend on the type of job. Programmers - sure, lots of different things work. We're a weird breed.
But your secretary HAS to be there every day from 8-5. Your phone and email customer support service people HAVE to be there during a specific set of hours and rotate in an organized way, and have set vacation times that don't overlap, etc.
When it comes to this kind of stuff with employees, it's always going to be tricky. There's always going to be exceptions to the rules.
Where I choose to work, I would personally like someone to tell me I have 2 weeks a year of vacation, and 1 week of sick time, or something to that effect.
For hours per week that I work, I would like that to be based on accomplishments, and NOT based on how long I'm sitting in my chair. I can spend 3 hours dwelling over a stupid problem, walk away for the night, show up in the morning and realize I misspelled a single variable.