All depends on the leadership. In some places, working 9-5 won't get you in trouble, but if you're not around to kibbitz with the management at 6, you're not going anywhere.
The place I work at seems to respect the work/life balance well. If I get in at 9:00, I'm one of the first people in. If I leave at 6:30, I'm just about the last person out. There are a few people who work odd hours, and people in management who work a lot extra, but I think it's mostly a matter of choice.
My boss works a lot of overtime, partly because he's stretched too thin, being a dev manager and responsible for coding being one of the few key people left who originally wrote (and still understands) much of the system, but I also think he likes it that way. He is always very clear that we are not expected to work extra hours under normal circumstances, and I don't believe he's ever actually asked me to work extra in the 2 years or so, I've worked for him (I have a few times, but very seldom.)
