My first house was in a bad neighborhood, but 5 years later it's gentrifying. My only real issue with the house was the semi busy side street it was on and noise. Yes, there were a few incidents in the 2.5 years I lived there, but just surrounding me, not directly affecting me other than a renter next door that was a PITA but got in trouble after the landlord and cops got involved.
I ended up moving to another house not on a busy street, and not in an unsavory neighborhood per say, other than the high number of section 8 rentals. The ghetto section 8 neighbor across the street ended up leaving me wanting to move to a more desirable neighborhood.
I think the moral of the story is that a bad neighborhood is really block specific. Your neighbors really make the difference, as does the specific house. I now talk to the neighbors when I buy. Several of them, not just one. I research the recent crime statistics, ratio of renters, income and education levels, etc. I've also found the grocery store a good meter of the neighborhood, since the characters there are representative of the types of people that live in the area.
I'm actually considering moving back to the "ghetto" just so long as the house is vetted well; not on a busy street and no ghetto neighbors nearby. Also keep in in mind, neighbors change all the time. At my first house the neighbors to the left, right and behind me changed in less than 2 years. Foreclosure on 2, renter in the other. Just pick the house carefully. Just pick the house carefully. Driving through the ghetto is one thing. Living next door to it is another...