I would have stayed at my first job much, much longer because I realise with hindsight that I had landed on my feet.
I wouldn't have taken so long out of the workplace to bring up my children, although I would still have needed several years. It was due to childcare costs and there really seemed no way around it at the time. I look back though and wonder if I could still have got back in just a little sooner. I will never know though, and I would never change the children I have. I just should have explored it more thoroughly.
That said, I am happy with the job I now have and with my work/life balance, so I haven't done too badly. As others have said, these things have helped shape the person I am today.