Oops.. reading the interesting thread "Blues vs. Rap", I now realize what would be the impression of people about my suggestion, if they visualize gangsta sub-culture as the present RAP shows it to us.
I feel that some clarification should be made: while there is an interesting phenomenon of tango raising from the marginal world and gaining a place in pop music, tango has never been an expression of anger or hate. It is melancholic indeed, sad, pesimistic, critics, and sometimes ironically humorous, but you'll never find a word about rape, drugs, or encouraging of crime of any kind. Furthermore, most of tango is not criminal, of course. Even in those like the one I was referring to, the most criminal expression you may find is "the clothes I took from his room". References to murder in other tangos are few, always in passional situations, and always in a context of grief and repentance.

Let's consider that tango was originated by the end of the 19th century, in the suburban area of Buenos Aires (where it took its roots in the Habanera, the country-folk Milonga and some African components) and was influenced by the late romanticism of classics too, and from its very beginning conquered the hearts of popular poets who immortalized so many masterpieces of true music.

Curiously, I personally choose spirituals, traditional and some jazz to perform when I'm for a solo. May be tango is too pesimistic for my taste, or I'm not a nationalist at all. I still owe to Kat a tape with my voice, then I'll record one tango and one spiritual :)
Un abrazo - Andrés