Baozi (1- ) [dumpling with soup in the dumpling] and rou (4) jia (1) mo (2) [meat between a bun... like a hamburger] that I ate in Xi'an (a great city for foreigners to visit... great history, culture and food).

In my country, it is 'kolokee' (I don't know the 汉字). It is basically sweet and sour chicken.

Are you talking about foods that originally come from China or foods cooked in a Chinese style? If it's the former, then I think fried rice easily would be considered most popular since it's a pretty standard home-made dish here, and people only consider the fried rice they get at Chinese restaurants to actually be Chinese. Spring rolls and prawn crackers are pretty standard entrees in Chinese restaurants, but they're not considered full meals here. I reckon the most demanded dishes are anything cooked in Sichuan style, in particular Sichuan beef and vegetable dishes.

For Americans, actually sweet and sour chicken/not pork would be most popular. Along with fried rice.

I am from Argentina and i like a lot the chop suey, and i think that is the most famous Chinese food here. Just me opinion, is really tasty. (;