Ways to manage something like a 'work-life balance'?
Disclaimer 1: I know the two worlds : academia and the outside world ;) I worked in public and private universities, and in a consulting firm.

Disclaimer 2: I can only speak about life for people involved in theoretical areas, I know that science involving living things / big experiments has real constraints.

I heard a lot of people in academia complaining about the conflicts between their work schedules and personal lives (me included, because I'm grumpy). But we have to face it, most of the time there is nothing to complain about it.


"I have a deadline today at midnight" : I do that all the time, but the calls for papers are out several months before the deadlines, so the problem here is planning, not the nature of the work.
"I have to finish this grant application before midnight" : hum, grant applications and conferences deadlines seems to be of the same kind.
"It's 3 AM, I just got that email that needs an answer" : I don't think this email is that urgent. An BTW, if something is really urgent, phone still exists for that matter.
"Someone (supervisor, head of the team, dean, etc.) wants me to work more/at night/etc." : Slavery has been abolished. If you have good results, the thing is that in academia you are master of your schedule.
"I cannot stop thinking about that problem" : yep, here this is true, we bring our work everywhere. If a researcher cannot live with that aspect of the work (which can be quite stressful), then he should probably consider finding an other job.


My point is that working in academia is working in one of the most flexible field. 
This is where there is a big difference with the "outside world". 
This flexibility is the problem: many people have difficulty dealing with it, and thus are giving themselves very strong constraints, so strong that they cannot handle them.