This seems like one of those things I should be careful about. Girls from any race or ethnicity CAN be attractive, but both for men or women, regardless of race, the majority of people are ugly. I was watching women's volleyball the other night, and both the white girls (why the hell does anyone say Caucasian?!!) from the American team and the black girls from the Cuban team were very attractive.
Also, calling blacks "African" is pretty racist, since you're denoting that they come from Africa. Why about whites who come from Africa? Hell, we all probably descended from ancestors who originally lived on Africa, so aren't all of us African?
Asian girls on average are the most attractive, since in this country, they're by far the thinnest race. At the end of the day, given the ideal girl, mine would be either White or Hispanic.