Definitely after. Especially having my eldest, it's corny but he gave me a purpose in life. Don't get me wrong, I look forward to the day my children fly the nest for their own lives, but being a parent was the piece of myself I didn't even know that was missing. Life before was pretty rubbish.
I can also absolutely understand how it's not for everyone though. I don't agree with the idea that anyone's life isn't complete without children. It's definitely a very individual thing.