It's not the word itself. It's that when a white person uses it, they're associating themselves with a school of thought that views black people as inferior. It's not the word itself, it's the message you send out by using the word.
-k
What about when someone like Bill Maher, who obviously doesn't believe black people are inferior, uses it? I understand how the word is seen and was used. I understand that he shouldn't have said it. I also understand that he used it as a comedian (not that it was funny).