Even if racism is gone, it will be replaced by other stuff. Religion, political ideas, sexual preferences, wealth, cultural differences, gender, nationality ...
Some people will always hate others that aren't exactly like themself. Wherever you go, there will always be groups of people that dislike each other. Sometimes out of a misplaced superiority complex (i'm superior, and people like me must be too), most of the time out of fear.
E.g. in Eastern Europe: Slavs vs gypsies. Europe: whites vs muslims. America: whites - blacks. Iraq: Shiites - Sunnis. Darfur: Arabs - blacks. India: muslims - hindoes. Congo/Rwanda: hutu - tutsi.
It's not the differences that are the problem, rather the people that can't deal with them and always feel threatened. Personally i'm all for mixing. I'm white and generally more attracted to non-white girls so there's a good chance i'll chip in my contribution.
Personally i give the human race another 100 years MAX to live as we know it.
Pretty soon genetically engineered humans will also come onto the scene. Maybe they'll feel superior as well...