Here's my two cents:
I'm black, and so far, none of my previous relationships have been with a lady of the same race as I (this being total coincidence, and not of my design.) The thing is... I never really thought that was a big deal until I noticed how often people brought it up. I've grown up around racism, and I don't think people's reactions were what you'd call "racist," but it just seemed like people would treat us differently at times, or make little comments. This struck me as odd because, as I said, I never really thought it was that big of a deal.
Then again, I grew up within driving distance of the international headquarters of the KKK, so I think it was a regional thing. @_@