I think they're the hottest! One of my exes was half African-American and the other half was a mix of native Hawai'ian and European. He was delicious in every way.
OK, by "mixed race" I mean guys whose ancestors 5000 years ago were on more than one continent. Mine, alas, were only on one, unless you count Western Europe and Eastern Europe as different continents, which I don't. (I do count Polynesia/Pacific Islands as a "continent" for this purpose; the native people in Japan, for example, are still oppressed by the majority population, who come from Korea originally.)
Note that most African-Americans are actually African-European in this sense. I'm an American by birth, but racially I'm European. A racial African American would be part African, part Native American/Indian/First Peoples.
Dean Cain (European-Asian) is one of my favorite examples. Yummy guy.
Just saw Leandro Okabe (European-Asian-?South American Native?) for the first time today. Some wonderful person posted a bunch of links to pics of him in this thread.
Who are your favorite mixed race guys? Post links if you've got 'em!