I grew up in New Jersey, a mere half hour from much-more-fabulous New York City. San Francisco is gorgeous and fun, but I don't think I could ever live there. It's way too car-dependent (commuter traffic on 280 is just brutal), it's weather never changes, and all those steep hills just don't make any sense. Whenever you park you have to fall out of your car to get out.
Little kids can live anywhere, because they go where their parents go. I'm wondering about the future, when my boys are older and seeking out entertainment on their own. When I was in high school, we couldn't just shlep into the city every weekend because there wasn't time; all that driving really cut into the few hours we had before curfew. So we mostly drove around looking for house parties, which sucks. My kids deserve better than mailbox baseball to kill a Saturday night.
My wife and I know we'll soon have to make some difficult decisions about the quality of life we want for our boys. And we've been procrastinating for too long, because the idea of having to leave our rent-stabilized apartment in Manhattan is too depressing. The three S's--space, schools, and screwball neighbors--are growing in importance, and we'll manage them as long as we can. We still love the city, and we'll probably stay until the sheer force of our belongings blows the front door off its hinges and spills our diaper pail into the hallway.