If the offensiveness of a word depends on what color the person is who said it, then the word itself is not offensive. A word that is truly offensive would offend regardless of who says it and in what connotation. Besides just saying a word isn't illegal. The fact that people are so hyper-reactive to a word is what gives it its power.
Yes, everyone should be allowed to say the "n" word, even though it is terrible when they do. In the United States, people have freedom to speak their mind, as long as they do not hurt others. This freedom is very important. Even though I think the "n" word is a terrible thing to say, people should be allowed to use the word if they want to.
I mean a word is word and I think it is how one uses it that may be the distinguishing factor on how one reacts to it if that makes any sense. I do not think people should get offended if someone uses it to refer to a genuinely ignorant person.
Go back to the history books. If black slaves did not act the way White folks wanted them to were punished, and in many cases, murdered. This word was invented by White people as a pejorative for blacks, used every time a black person was beaten, insulted, raped, lynched, whipped, and mistreated. It was a tool of oppression.
Not everything should be "in bounds" to us as white people. White women can hopefully begin to (though never fully) understand this when you think about the ways in which you are denied voice and space by dominant men.
Just because we are not welcome to use one word in the English language does not mean that we are being discriminated against.
Just because we cannot say the word, but a black man can, DOES NOT mean it's a DOUBLE STANDARD. It's something that society must expect already. It wouldn't be bad if I kissed my fiancé, but if YOU kissed my fiancé, that would be. . *That* is not a double standard. Even though I can kiss my fiancé, doesn't mean you can too.
White people used it as a slay towards black people for hundreds of years and they still say nigger towards us now. Black people took the 'er' off of the word and put an 'a' to make an obvious distinction between the two words. We use it as a friendly term towards each other, so I feel that white people shouldn't be able to say it since they had it for hundreds of years anyways. Just my two cents.