I have no idea what the go to word is for black people. Whenever i am referring to someone of a different color I say it. Like that black dude. I've also been known to say that white dude, ill even call another white person a cracker simply because I don't care. If you are that easily offended by a word then you should stay in your house or when filling out a form tick decline to answer or write in your preference of whatever race you are. Its all for census anyway.
Also, the phrase nigga can be used by white people if you use it properly. Be confident with your surroundings and you need not worry. some people in this forum will throw around the term racist for anything, and all that does it tell me that they would never enter a black neighborhood and more than likely never been raised in a setting like that. When you have white ppl calling others racist in support of black people is completely ignorant imo. Or when you call someone racist for being proud of their race is just idiotic.
I for one am not going to walk around saying "damn I wish I was black" just because some think being proud to be white is racist. Lastly, I don't get offended by a piece of paper asking what my race is, its childish, pathetic and a waste of energy to even worry about it.