The main problem I see in this thread is that many people seem to believe that racism is confined to white on black, or 'slavery racism' if you will. Since the dawn of time just about every single sect of humanity has believed that they were the 'superior race' when they encountered a different culture.
Some examples and the various time periods they cropped up:
German 'Aryan Race' - 1920's - 1940's - generally perceived as racism against Jews, but in point of fact the Germans separated the races into various tiers, with Aryans at the top and Jews at the bottom.
Japanese vs the 'yellow dogs' (Chinese) - first contact of races, honestly don't know off the top of my head, somewhere around the 2nd or 3rd century AD - pretty much since the two races first contacted each other, both sides believed they were the superior race. I can't off the top of my head remember the slurs that the Chinese applied to the Japanese, but rest assured that both of them were confident in their race's superiority
Portugese 'barbarians' vs the Japanese 'monkeys' - 16th century Portugal 'discovered' Japan, the Portuguese and Japanese once again were both convinced that they were a superior race. After a very turbulent period, the Japanese actually expelled ALL foreginers from their country for over two hundred years from the 17th to the mid 19th century.
English (later the Americans) vs the Native Americans - Pretty much ever since they landed in America, for the most part the Native Americans were agreed to be a 'lesser' race. This instance of racism actually has a reason behind it - if they were an inferior race, they could not own land (that the settlers wanted). Clearly, they were an inferior race. I don't know too much about Native Americans, but from what I understand this was a two way street as well, the Native Americans looked at the English as barbarians for their disrespect for the land and animals.
I could continue on with these examples, but the point remains that pretty much since two different cultures encountered each other, both sides believed that THEY were the superior race. The idea that racism is bad is actually an extremely modern concept. However, even though racism (discrimination through skin color) is considered 'bad', people will simply find other reasons to think they are superior - intelligence, physical appearance, wealth, jobs, whose wife is hotter, dick size, whose truck has bigger engine, who killed a bigger gator with a 2x4, who has more wives/children, etc. People will continue to believe that they are superior to other people until humanity ends.