Somewhat to my surprise, this thread has been a captivating read, though personally I think there have been some comments and attitudes that show the murkier side of human nature.
My view is that colour of skin has absolutely zero impact on who I would or would not go out with. Cultural background might, but skin colour would not.
So, when talking about another "race", I'd need to define exactly what I meant by that. Going out with a girl from some backgrounds, perhaps such as (but not limited to) Asian could cause problems. I would not, for instance, be prepared to spend very long hiding the relationship from the girl's family. That might, in turn, cause a level of aggravation that just wasn't worth dealing with.
So, it'd be her cultural background, in that case, that would be the issue, not her race.
Personally, I regard racial differences as entirely superficial, and the planet would be far better off if we were all the same in that regard, whatever race that was. It's one of the reasons I like forum chat - you can have a discussion (be it quiet, heated or intense) without even knowing the background of the person you're debating with, so you can't have any preconceptions about their stance, position or opinion. The same is true of age, sex and educational background.
So no, a girl of another race would hold no problems for me. Another culture, however, ..... maybe. It would depend on what happened. My main criteria for selecting a girl to spend time with is what's between her ears. Looks, let alone colour, is very peripheral to that. I want someone who's company I enjoy, who I want to be with, spend time with, and nothing that doesn't affect that matters.