First off, for context: I'm a heterosixual male with predominantly Germanic and Celtic ancestry, with wee little bits of various eastern European peoples thrown in. I'm a natural American citizen, and all branches of my family have been American for long enough that we stopped keeping track.
Also, obviously, this post is all about sweeping generalizations. This whole post is totally destroyed by specific examples.
Ethnically, I prefer those of Irish descent above all else. I think fair skin & freckles are beautiful, I feel that red hair and green eyes create a beautiful compliment, and women of Irish descent are often of a compatible height for me (shorter, but not so short as to be awkward). They're also just generally pretty. Otherwise, I find ethnically Slavic, Khmer, Persian, and Semetic, women to often be very attractive. Africa is waaaay to ethnically diverse for me to really break down my top picks, but basically my top picks mostly center around the equatorial coastal regions.
Nationally, to me attraction really comes down to history more than appearance (since nationality has little to do with appearance), so my response is a bit different. Basically, I find that nations which have (A) great hardships and (

good educational opportunities produce the most attractive women. However, since I've only lived in America, I've had limited opportunity to meet such women, and I've never managed to get anything going with one, so this might not be quite so true as I think. But of those foreign women I've met, I've found that, for example, the girl who survived genocidal war in eastern Europe as a child is far more attractive to me than any of the foreign exchange students from Denmark.
Phonetically... I'm all over the place. Really, I just like accents. Except for Chinese, Korean, Indian, British, German, American, Latin-American, and Australian accents.
So, I suppose that ultimately I'd probably find Isreali women to be the total most attractive.