I live in DC (the city itself, not the suburbs) and I love my neighborhood. Not too long ago this was a scary area but there has been a lot of revitalization in the city, especially in the last 10 years, and crime has dropped a lot in most neighborhoods. It's a very vibrant city and I can't imagine living anywhere else.
The suburbs are a nightmare, in my opinion. On the Maryland and Virginia sides, traffic is jammed from 6 in the morning till 8 or 9 at night, and on the weekends most middle-sized roads are snarled with people running errands in their giant SUV's. Crime in some of the Maryland suburbs, particularly Prince George's County, is on the rise. Property taxes in the suburbs are a lot higher than in the city itself.
Real estate is extremely expensive, does not matter if you are looking in the city or in the suburbs, so bring your giant box of money when you move. You can get "more house for the money" in the city than in the suburbs, unless you are willing to move very, very far out of the city, which I don't recommend unless you have an off-hours commute.
As far as raising a family goes, it takes a little more work for the parents to line up and supervise play-time for the kids, because you really need to supervise them, not just let them outside when it is play-time. But the same goes for any large city.