1) Hispanic;
2) White;
3) Black;
3) Asian.
Not really sure about Arabs, but I find Irani women quite attractive. I think I'd put them on par with white girls in my list. I think one of the most beautiful girls I've ever met was from Iran. Too bad I'm infidel, lol, didn't end well...
Not really sure about black placement either, cuz if I refer to negrita from Puerto-Ruco or Peru, then it's #1...