I don't think it's okay to say it at someone, but I think it's okay to say it when discussing the word itself. Even then, I hesitated for some time before deciding to post it.

It's such an interesting word. Some people cannot bare seeing or hearing it. Some use it as a slur, others use it as an endearing term. Some refuse to ever say or write it.

I don't think there are any other words in the English language that are as polarizing as the word "nigger ".