regardless of who says it i think it's an absolutely repulsive word that should be removed from the english vocabulary. period.
i don't think any non-blacks should be saying it at all or EVER; whether or not their black friends are ok with them saying it or not is irrelevant. have some moral/historic context. the word has its roots in genetic superiority/master race type bullshit, and treating another race as less than an animal. aside from the near genocide of the native americans, possibly the ugliest aspects of your american history.
as for blacks saying it to each other as a term of 'endearment', that's a discussion black people should have between themselves, and really not for anyone else to decide for them.
beyond that i truly don't see people as 'black' or 'white', or 'asian' etc etc. not anymore. i just see us all as collectively 'humans'. i know this sounds cliche and sappy, but when you discover how/why the 'race' issue was ever invented and it's purpose, you change your entire awareness of an issue.
and anytime anyone of us get caught up in race debates, we let those rich elite assholes continue to divide & conquer us. imo.