Oh yes, and I fully expect the 'racist' accusations to pop up any minute now.
I'm not trying to be antagonistic at all here, but if your roommate is black, please say it directly. There's nothing wrong with pointing it out; black people and white people are different culturally. On the other hand, it is wrong to use racially coded language to imply that he's black ("gangsta", "hood"), so don't do that. If he's not black, then it just sounds odd to use those words.
I take issue with your statement that "black people and white people are different culturally." That's a broad generalization. Yes, he happens to be black. Yes, he happens to enjoy rap and hip hop. We'd be just as different from each other if he were white or I were black. And for the record, I would've used the same language despite his race -- it doesn't sound odd to me if used in that context, personally.
Come on Scott, you don't see how describing your black roommate as "gangsta" and "from the hood" might make people a little uncomfortable? I'm not saying you were being consciously malicious but that kind of language is a bit troubling. I don't think anyone associated "gangsta"/"hood" with the idea that your roommate might be anything other than black, expressed in a strange
wink, nudge manner.