I don't have first-hand experience, so obviously I could be wrong, and if I've mischaracterized the culture, correct me. But here're a few points I've noticed:
1.) The obsession with "bling" and personal status through high-priced consumer goods. I've read that it's poor urban kids buying those $200 Nikes, and then marketers hope that their tastes will filter down into middle-class American kids. The street kids on the subway often have more stylish clothes and accessories than rich white kids. Remember Ludacris's song "Glamorous"?
2.) Anti-intellectualism. I have a couple friends who teach in inner-city school system. When black kids do well in school, they're taunted and teased by their classmates for "acting white". There's a strong cultural pressure not to stick out or excel.
3.) Gang warfare and revenge killings. There was a shooting a block away from my workplace a couple of years ago. A few gang members had apparently been slighted, so they got in a car, hunted down the rival gang member responsible, and shot him in a drive-by.
I think there's a bit of bias as an outsider looking in, so here are my comments, having been a bit closer involved in "black culture," as it were.
1) Obsession with personal status isn't one of the points of Thar, at least not as expressed by the collecting of property. And black kids aren't alone in buying clothes that outwardly indicate their high price, although they might be alone in buying rainbow colored AF1's.
2) Anti-intellectualism is an interesting point which I'll grant does show itself in middle and high school aged kids. I think if you ask those kids (or their parents) if education is important, however, I think they'll all say yes. I haven't actually tried it, but I've never met a high school dropout (of any race) who didn't regret it. Inner city schools are filled with kids who, by high school, have often given up on themselves, and the "acting white" expressions are sort of a outward expression of that frustration. Rather than muddle this too much with socioeconomic rhetoric, I'll just say that one look at MySpace and another at Facebook demonstrates there are plenty of kids steeped deep in hiphop culture who are getting their four year degrees.
3) Gang warfare among blacks is probably comparable in degree to that seen with the Mafia and various Hispanic gangs. I don't think your standard Italians, Hispanics, or black people are gang banging, no matter how hiphop or "urban" they are.
