As a parent (of now a teenager who is barreling towards college) - I would advise to work a lot, but work will always be there. Your kids will not. Your life should be what you do when you are not working - not the other way around.
Many years ago, I was working 80+ hour weeks, week after week, and my daughter was very young. Consistently, I would not even SEE her from Thursday morning until Saturday afternoon.
I burned out on that job. I felt shell-shocked. I went to dinner with my wife and realized that we had grown apart. I hated that. I hated missing my daughter growing up.
I hated that my daily thoughts were about work, what was happening with work, and that my interactions with my coworkers had overridden my interaction with my family.
So I decided that my life would revolve around my family, and who I was outside of work, not the other way around. Over the years I have changed jobs, started companies, had wild success, had some failures, but through it all I felt even-keel because it all felt like my LIFE was the same. The cubicles, the coworkers, the employees, those all change but my wife and daughter, the life we share, that has been constant. I actually don't feel like I've changed jobs at all even though in reality I've worked at about 6 different places and started 2 companies.
Don't think that work and success will make it alright in the end. It won't. Don't believe people who think you are slacking because you aren't working 100 hours a week. Those people aren't executing efficiently. I can promise you this is true because I have left a trail of Type A 'go-go-go' personalities in my wake because they couldn't match my output and drive, even though they were burning midnight oil and I was at home watching Jeopardy! with the fam.
I guess what I'm trying to say is don't listen to all of those people who are making horrible mistakes. Work hard, but read 'The Power of Full Engagement' by Tony Shwartz and realize that you can work like mad and relax and you will beat the crap out of everyone around you.